1Combine brown sugar, white sugar, cinnamon, melted butter, and a pinch of kosher salt in a large bowl and mix until saturated and resembling a thick, gooey mixture.
2Add all-purpose flour to the butter mixture and mix by hand until all flour is incorporated and a crumbly topping is formed.
3Cream together softened butter and sugar in a mixer until fluffy.
4Whisk eggs and vanilla extract together in a separate container.
5Add the egg and vanilla mixture to the creamed butter and sugar, mixing until just incorporated.
6Combine flour, baking powder, baking soda, and salt in a bowl.
7Fold the dry ingredients into the wet ingredients until just combined, ensuring not to overwork the batter.
8Mix in sour cream and milk until the batter is smooth but still thick.
9Butter and line baking pans with crumpled parchment paper.
10Spread about half of the cake batter evenly into the prepared pans.
11Layer a good amount of the crumb topping over the batter and gently press it into the batter.
12Add the remaining cake batter over the crumb layer, spreading it out evenly.
13Top with more crumb topping, pressing it gently into the batter to ensure it sticks during baking.
14Bake in a 350-degree Fahrenheit oven for approximately 35-40 minutes, or until a toothpick inserted into the center comes out clean.
15Let the coffee cake cool to room temperature before serving.
Ingredients
1 lb brown sugar
1 cup granulated sugar
1 lb melted butter
2 tbsp ground cinnamon
pinch kosher salt
1.5 tsp vanilla extract
4.5 cups AP flour
0.5 cup softened butter
0.75 cups sugar
2 eggs
2 tsp vanilla extract
1.33 cups AP flour
1 tsp baking powder
0.25 tsp baking soda
0.25 tsp salt
0.5 cup sour cream or Greek yogurt
2 tbsp milk
Equipment
large bowlwhiskmixerspatulabaking pansparchment paper
Tips
Crumple parchment paper before lining pans to make it easier to line.
Press the crumb topping into the batter to ensure layers stick together after baking.