1. Preheat the oven to 350 degrees Fahrenheit.
2. Wash and cut the apples in half lengthwise, removing the core, stem, and bottom. Slice them into ⅕ inch pieces.
3. Crack the 4 eggs into a large bowl and use an electric mixer to beat them. Mix until it turns bubbly.
4. Add the vanilla extract to the eggs. While mixing gradually add sugar.
5. Add baking powder to the bowl and keep mixing until the mixture is white (or close to white).
6.Finely grate orange peel into the bowl for flavor
7. Add the sour cream to the mixture. Sift the flour into the bowl. Add a pinch of cinnamon and use a spoon to mix until smooth.
8. Prepare a circular pan (approximately 7 inches in diameter) by greasing the sides with the butter and sprinkle some sugar on the bottom. If you don’t have a pan whose sides snap on and off, lay a sheet of wax paper on the pan.
9. Cover the bottom of the pan with a portion of the sliced apples and sprinkle them with cinnamon.
10.Pour egg and flour mixture over the pan with the apples.
11. Arrange the rest of the apples on top of the batter in whichever pattern you like; just make sure to use up all the apples and cover the mixture completely.
12. Sprinkle a bit more cinnamon on top.
13. Put the pan in the oven for 30 minutes to bake.
14. Take the pan out and let cool for 10 minutes.
15. Enjoy! Lilaya recommends this with a hot cup of black tea with lemon and sugar.