Preheat the oven to 350 degrees. Grease and flour a pan. Set aside for later.
In a bowl combine the spices, baking powder, flour, oat flour and brown sugar. Set aside
In another bowl mix the butter with the eggs, yogurt and vanilla extract.
Pour the wet ingredients into the dry ingredients and incorporate with the help of a rubber spatula. Pour the batter into the prepared pan. Decorate with the apple slices and take to the oven. Bake for 35 to 40 minutes or until done.