Cut peeled sweet potatoes into small cubes and place in a medium pan with water, bring to boil and cook for 15 minutes, or until they are soft. Mash and set aside to cool.
Pour warm milk into a bowl and add yeast. Let it sit for about 5 minutes, the mixture should start frothing up.
In a large bowl, mix together the flour, sugar, spread or butter and salt.
Add cooled and mashed sweet potato into the yeast mixture and stir together.
Pour milk/ yeast and sweet potato mixture into flour mixture and using the dough hook of electric mixer (you can also use your hands for kneading the dough), mix well until all the ingredients are well incorporated and you have a smooth dough.
Place the dough into an oiled bowl and cover with cling film. Allow to rise for an hour or until doubled in size.
Turn the dough out onto a lightly floured surface and roll into rectangle, roughly about 18 inches long and 12 inches wide. It should be roughly ¼ inch thick.
Mix together the brown sugar and cinnamon. Spread the butter across the dough, leaving small gap on each side. Sprinkle over the sugar and cinnamon mixture. Working carefully from the long edge, roll the dough down to the bottom edge. Using a sharp knife or a floss, cut the dough into 16- 18 equal pieces (the amount will vary, depending on the length of your dough).
Grease baking pan or tray, and transfer you rolls into it. Cover with cling film and allow to rise for another 30 minutes or until they have doubled in size. Pre-heat the oven to 170 C (temperature may vary, depending on the oven type).
Bake for 20 minutes or until golden brown. Allow to cool for 10- 15 minutes. In a mean time, mix together the icing sugar and milk. Drizzle rolls with icing sugar. Enjoy!
*Milk should not be too hot, it should be luke warm.*The amount of rolls may vary, depending on the size of your dough.*Rolls are best served fresh, on the same day, but will keep in the air- tight container for a couple of days.