Preheat oven to 350 degrees and line a 9x13 baking dish with parchment paper.

Cream butter and sugar together in your mixer until light and fluffy. Add in eggs one at a time, add vanilla.

Sift together flour, baking powder, salt and cinnamon.

Add flour mixture and sour cream, alternating, starting and ending with flour. Mixing just until each addition is incorporated into batter.

Spread batter into prepared pan.

Peel, core and slice apples into thin slices (about 16 slices per apple) place apples in a single layer across top of batter.

Combine sugar and cinnamon for topping. Sprinkle over top of apple layer.

Bake for 40 minutes, or until toothpick inserted in center comes out clean.

Remove cake from oven and let cool 30 minutes.

Prepare glaze: combine powdered sugar, milk and vanilla, stirring until smooth. Drizzle over top of cake. Serve cake still warm or can be served cooled.

Store in refrigerator.