Preheat oven to 350 degrees and grease a springform pan.
In a medium mixing bowl, cream butter and sugar until light and fluffy.
Add eggs, one at a time, and beat until combined. Add flour and baking powder and mix until just combined.
Spread batter into springform pan. Top with apples, starting with a ring around the outside of the pan, moving toward the center, with lots of overlap.
In a small bowl, mix together sugar and cinnamon. Sprinkle over the apples.
Bake 60 minutes, until a toothpick comes out clean. If cinnamon sugar on top is still raw, broil 3-5 minutes until browned.
Notes
It may not be traditional, but it’s perfect with a scoop of vanilla ice cream and a bit of caramel sauce.