This apple crumble cake is made with gently spiced, brown sugar sponge, a filling of fragrant and aromatic cinnamon apples, and a silky-smooth custard buttercream. A generous layer of the crumble topping adds even more flavour, as well as a delicious crunch!
As each element of this layer cake can be made ahead of time, it's a great recipe to prepare in advance and assemble on the day of serving.
Apple crumble cake is different than an apple crumb cake or an American-style apple coffee cake. This is more of a British classic pud, but turned into a cake. It's full of warming, autumnal flavours and will be great for any seasonal celebrations and occasions.
The layers of spiced sponge are sandwiched with lush and super smooth custard buttercream, and filled with satisfying, cosy and delicious stewed apples cooked in butter, cinnamon and brown sugar. Finally, the cake is topped with the classic crumble mixture to add a lovely crunch and even more of the buttery, cinnamon flavour.
Apple crumble cake consists of four separate components: the crumble topping, the custard buttercream (also known as German buttercream or crème mousseline), spiced apple filling and the sponge.
- The sponge is made from the following ingredients: butter, soft light brown sugar (packed light brown sugar), eggs, self-raising flour, ground cinnamon, milk and salt.
- For the crumble topping - plain flour, soft light brown sugar (or demerara sugar if you want even better crunch!), ground cinnamon, salt and butter.
- Apple filling - apples, cinnamon, soft light brown sugar, butter.
- Custard buttercream, also known as German buttercream, is made with whole milk, vanilla, cornflour/ corn starch, sugar and eggs. This type of buttercream is lovely and light, with silky-smooth consistency and is also less sweet in comparison to all the other types of buttercream.
Scroll to the bottom of this post for the recipe card and the full list of the ingredients.
Just like any layer cake, it is best if you give yourself a bit of an ahead start with this apple cake. It will make the rest of the process much quicker and much easier. I recommend starting it a day ahead, and leaving just an assembly for the day you are planning on serving the cake.
Make the custard and cover it directly with the clingfilm. Allow it to cool, then whip it with soft butter to make the buttercream.
Prepare the apple crumble topping and store in an airtight container until you need it.
Stew the apples until they are soft and cooked. Set them aside and cool completely.
Bake the sponges and allow them to cool completely before assembling the cake.
Hint: Reserve the liquid and all the juices from cooking the apples. Use it to soak the sponges with. This will keep them moist and add even more flavour to the cake!
When all of the cake components are ready, it's time to assemble the cake. The process of putting this apple crumble cake together is super easy, and it should only take few minutes, providing that you have everything ready.
Hint: If your sponge cakes have domed tops, level them up with large serrated knife or with the cake leveller. Alternatively, if you don't feel confident in doing so, turn the sponges upside down.
Place the first sponge on a plate or cake board. Poke the sponge surface with a skewer and brush with some of the liquid from the apples. Pipe the buttercream around the sponge.
Spread a thin layer of custard buttercream on the top of the sponge. Use the back of the spoon or an offset spatula to do so.
Add an even layer of stewed apples on top of the custard cream. Top with the second sponge and repeat.
Top with the last remaining sponge. Poke the sponge with skewer and brush with the juices from the apples. Pipe the icing over the whole top of the cake. Add the crumble topping on top to finish.
- Soft light brown sugar - This type of sugar works best in this cake recipe as it will add these lovely, buttery caramel notes and the darker colour to the cake, the filling, and to the crumble. You can use golden caster sugar or granulated sugar instead, but it will alter the taste and the look of the cake.
- Flour - Use the plain/ all purpose flour for the crumble topping, and self-raising flour for the sponge. Alternatively, you can also make the sponge with plain flour, just remember that you have to add baking powder to it (I suggest adding 2 teaspoon of baking powder for this recipe).
- Butter - Salted or unsalted butter is fine to use. If using salted butter, you may want to reduce the amount of salt in the crumble and the in the cake batter.
- Apples - I like to use the Granny Smith apples in this recipe, as they are sweet and tart and keep their shape well when cooked, but feel free to use your favourite type. Cox or Gala apples will also work very well here. Bramley apples may not be the best choice as they tend to go mushy when cooked.
- Custard buttercream - If you never made this type of buttercream before, you may want to check out this German Buttercream recipe for some detailed instructions. As an alternative, use your own favourite type of buttercream.
- Use different fruit, nuts and spices - swap the apples for pears and add some other warming spices like nutmeg, cloves, allspice, or cardamom to enhance the flavour of this bake. Adding a handful of chopped pecans or walnuts will also work really well in this cake recipe.
- Try different icing or buttercream - feel free to use your favourite type of icing or buttercream with this cake. If you don't fancy making the custard buttercream from scratch, you can use the shortcut where custard powder is used instead, like in my apple crumble cupcakes recipe.
- 20 cm round sandwich tins - You will need 3 round 20 cm sandwich tins. If you only have one or two, just bake one or two sponges at a time.
- Piping bag with nozzle - Both are optional. I used Wilton 8B nozzle, but feel free to use your favourite type. If you don't have a nozzle, simply snip the end of the piping bag and pipe the buttercream without it, directly from the piping bag. No piping bag or a nozzle? No problem, just spread the buttercream over the cake.
- Cake leveller - this is an optional tool, but very helpful for levelling the sponges precisely. Alternatively you can use large, sharp serrated knife.
- Digital kitchen scales - For precise measurements of the ingredients.
- Fine kitchen sieve - Making of the buttercream will require you to push the custard base through a fine sieve to get rid of any lumps.
Store any leftovers of this apple cake in the airtight container at room temperature for up to a day, or in the fridge for up to 2 days.
The sponges can be made ahead of time and will keep in the fridge for up to 2 days. Be sure to wrap them well in clingfilm, to prevent them from drying. You can also freeze the sponges for up to 3 months.
Crumble topping can be stored in the fridge for up to 4 days, or it can be frozen for up to 2 months.
You can make custard buttercream up to 2 days ahead and store in the fridge. You may have to re-whip it before using it. This buttercream is also suitable for freezing for up to 3 months.
Apple filling will keep in the fridge for up to a week. The butter will solidify, when making ahead, so just use a microwave or place the apples in a small saucepan to heat up gently. You can also freeze it for up to 3 months.
Frequently asked questions
I haven't tested this cake with gluten free substitutes, but I believe that it will work absolutely fine. Be sure to use good quality, gluten free self-raising flour, or if using plain gf flour, make sure the baking powder and baking soda are also gluten free. Cornflour in buttercream is also naturally gluten-free, but double check the packaging to be completely sure.
I recommend using Granny Smith variety, but Cox or Gala apples will also work well. Try avoiding the Bramley apples, or the cooking apples as they will turn mushy after cooking.
This can happen if you over-mix the crumble or if the butter used was too warm. Remember to use cold butter and only use your fingertips to rub it into the rest of the ingredients. You want a mixture of fine crumbs, as well as some lumpy bits for the best result. I also find that using the demerara sugar adds the most incredible crunch to the crumble topping!
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Apple Crumble Cake
- hand-held electric mixer or freestanding mixer with the paddle attachment
- 3 20 cm round sandwich tins
- baking paper
- Piping bag optional
- decorative piping nozzle of choice optional (I used Wilton 8b)
- fine kitchen sieve
For the crumble topping:
- 90 g plain flour
- 60 g demerara or soft light brown sugar
- ½ teaspoon cinnamon
- ½ teaspoon salt
- 60 g butter, cubed chilled
For the custard buttercream (German buttercream):
- 450 ml whole milk
- 2 tsp vanilla extract
- 135 g caster or granulated sugar
- 30 g cornflour/ corn starch
- 2 large eggs plus 2 extra egg yolks
- 250 g butter, diced room temperature
- ¼ teaspoon salt
For the apple filling:
- 4 large apples, peeled, cored and cubed (400g)
- 50 g butter
- 70 g soft light brown sugar
- 1 teaspoon ground cinnamon
For the sponge:
- 250 g butter room temperature
- 250 g soft light brown sugar
- 4 large eggs
- 250 g self- raising flour
- 1 teaspoon ground cinnamon
- ¼ teaspoon salt
- 1 tablespoon milk
To make the crumble topping:
- Preheat the oven to 180°C (160°C fan) and line a large baking sheet with baking paper.
- Place the flour, demerara sugar (or soft light brown sugar), cinnamon and salt in a bowl and mix to combine. Add the chilled butter cubes and using your fingertips, rub the butter into the rest of the ingredients until they all have come together and the mixture has crumb-like texture. Ideally, you want to have a combination of smaller and bigger crumble clusters.90 g plain flour, 60 g demerara or soft light brown sugar, ½ teaspoon cinnamon, ½ teaspoon salt, 60 g butter, cubed
- Transfer the crumble mixture into the baking sheet and spread it into an even layer. Place in the oven and bake for 15 minutes. Remove from the oven and cool completely.
To make the custard buttercream (German buttercream):
- Pour the milk into a large saucepan set over a medium heat and add vanilla. You want to heat the milk until it is hot, but do not bring it to the boil.450 ml whole milk, 2 teaspoon vanilla extract
- In a large bowl, combine together the sugar, cornflour, eggs and egg yolks. Whisk until you have smooth, thick mixture. Remove the milk from the heat and add it GRADUALLY into the egg mixture (in 4-5 additions), whisking constantly. Avoid pouring too much of the hot milk in one go, as you will risk scrambling the eggs.135 g caster or granulated sugar, 30 g cornflour/ corn starch, 2 large eggs plus 2 extra egg yolks, 250 g butter, diced, ¼ teaspoon salt
- Pour the mixture back into the saucepan and return to the heat. Cook for 5-7 minutes, stirring often, until it has thicken. Remove from the heat and push through the fine sieve into a large bowl, to get rid of any lumps. Cover the surface directly with clingfilm to prevent the skin forming, and allow it to cool completely.
- Once the mixture has cooled completely, whisk it briefly, using handheld electric mixer or standing mixer with the balloon attachment. Gradually start adding the softened butter, beating well after each addition and scraping the bowl as and when needed. Once all of the butter has been incorporated, whisk it for another couple of minutes. Reserve roughly ⅓ of the buttercream, then transfer the rest to a piping bag fitted with the nozzle of choice.
To make the apple filling:
- Melt the butter in a medium saucepan over a medium heat, and add the chopped apples, sugar and cinnamon and mix to combine. Cover with lid and cook gently for 7-9 minutes, stewing the apples gently until they are soft and cooked, but not mushy. Remove from the heat and set aside.4 large apples, peeled, cored and cubed, 50 g butter, 70 g soft light brown sugar, 1 teaspoon ground cinnamon
To make the sponges:
- Preheat the oven to 175°C (160°C fan). Lightly grease the cake tins and line the bottom of each with baking paper and set aside.
- Cream the butter and the sugar using an electric mixer or freestanding mixer with the paddle attachment until pale and fluffy, about 2-3 minutes. Add eggs, one at a time, mixing well after each addition. Add in the flour, cinnamon, salt and milk and whisk until combined.250 g butter, 250 g soft light brown sugar, 4 large eggs, 250 g self- raising flour, 1 teaspoon ground cinnamon, ¼ teaspoon salt, 1 tablespoon milk
- Divide the batter between the cake tins (use kitchen scales if you'd like for the precise measurements), smooth the top of each with the back of the spoon or a spatula and bake for 15 minutes, or until the sponges are springy to the touch and the toothpick inserted in the middle comes out clean.
- Remove from the oven and cool for 5 minutes, then remove from the baking tins and transfer to a cooling rack to cool completely. You can also wrap the cooled sponges in clingfilm and transfer to the fridge at this stage, if you are making this recipe ahead.
To assemble the cake:
- Drain the apples from the cooking liquid/ juices. Pour the juices into a small bowl or a jug. Place the first sponge on a plate or cake board and using a toothpick or a skewer, poke the surface of the sponge. Brush the top of the sponge with the reserved apple juices/ cooking liquid.
- Spread a thin layer of the buttercream on top of the sponge, then pipe the buttercream around the edges. Add a layer of apple filling, then top with the second sponge, repeating the process. Top with the last remaining sponge, poke the sponge with the skewer and brush with the cooking juices.
- Pipe the buttercream on the top of the sponge. Sprinkle the crumble topping on top of the buttercream. Slice and enjoy!
Please note that all my recipes are developed and tested in metric grams. I recommend that you use digital scales for a more accurate results. I have provided a conversion to US customary in the recipe but please note that I haven’t tested using this method.