Peel and dice the apples. In a pan melt the butter with sugar and cinnamon. Add the apples and cook for about twenty minutes. Let them cool.
In a bowl mix the ricotta, starch, coconut and sugar. Transfer the mixture to a pastry bag.
Beat the eggs with sugar for a long time, add the oil, mascarpone and sifted flour with baking powder. Continue to whip until you get a nice smooth and dense dough.
Butter and flour a mold (diameter 24 cm) and pour half of the dough. At this point add the ricotta cream forming a circle, then the caramelized apples and finally cover with the remaining dough.
Bake in a preheated oven at 170° ventilated mode for 40 minutes. Once cooked, let it rest for 5 minutes and unmold the bundt cake. Serve with a sprinkling of icing sugar if you prefer.