In a large bowl or mixing jug, combine together the sugar and an egg. Whisk together until combined. Add mascarpone cheese and cream and mix until well combined and no lumps and clumps appear. Add lemon zest and vanilla and whisk again. Pour the filling into the pastry case and arrange raspberries on top.
Bake in the middle shelf of the oven for about 20 minutes until pale golden and just set in the middle. Allow the tart to cool to room temperature, then transfer to the fridge for about 2 hours. Slice and enjoy!
For homemade pastry case, follow this recipe You can skip the refrigerating the baked tart for 2 hours, but it helps to firm it up and the tart is much easier to slice and holds it shape.You can replace raspberries with your favourite berries.