Put the grated apple with sugar and cinnamon in a pan and cook over medium heat until the liquid evaporates. Caution: the filling must be dry; if it stays watery it will make the dough soggy. Set aside to cool.

Beat the softened butter, vegetable oil, and powdered sugar. Add the yogurt and baking powder, then add the flour little by little until you get a soft, non-sticky dough.

Take a walnut-sized piece of the dough and flatten it in your palm, place a dessertspoon of the cooled apple filling inside, seal it, and roll into a ball. Arrange on a baking-paper-lined tray.

Bake in an oven preheated to 180 degrees for about twenty-five minutes, until lightly browned on top and bottom. Serve once cooled slightly.