Step 1

Preheat oven to 350 degrees F. Lightly grease a 9x13-inch baking pan and set aside.

Step 2

In a large mixing bowl, cream together butter and white sugar until light and fluffy, or about 3 minutes.

Step 3

Mix in eggs and vanilla until combined.

Step 4

Gently mix in sour cream. Add flour, baking powder, baking soda, salt, and cinnamon. Fold carefully into wet ingredients until just incorporated. Pour batter into prepared pan.

Step 5

In the same (now-batter-free) bowl, combine both sugars, flour, and cinnamon. Cut in butter with a fork or using your hands until mixture resembles wet sand. Crumble evenly over batter.

Step 6

Bake cake in oven for 25-28 minutes, or until crumb topping is crispy and a toothpick inserted into center of cake comes out mostly clean.

Step 7

Slice, serve, and enjoy!