1. Preheat the oven to 350°F, grease 8×8-inch baking pan and set aside.
2. In a medium mixing bowl mix together cored and sliced apples, lemon juice, granulated sugar, and cinnamon. Set aside.
3. In a large bowl sift all dry ingredients (all-purpose flour, baking powder, baking soda, and salt) and set aside.
4. In another mixing bowl, using a spatula, cream together softened butter and granulated sugar until smooth consistency. Add eggs, lemon zest, and vanilla extract and whisk. Add sour cream and milk and whisk it again.
5. Add dry ingredients to the mixture. Using a spatula, fold the ingredients together until well combined.
6. Pour the batter in the baking pan and top it with sliced apples, covered with sugar and cinnamon, in three rows. Bake at 350°F for about 35-40 minutes or until a toothpick comes out clean.
7. Remove the cake from the oven and let it cool off before serving. Enjoy!