Sour Cream Coffee Cake with Cinnamon Streusel

Created by: SugarAndButter

Ingredients

Instructions

1. Preheat and prep your panPreheat oven to 350°F. Grease a 9x13-inch baking pan really well — butter or nonstick spray both work. This cake is heavy with streusel, so you want every inch coated so it lifts out cleanly.
2. Make the streusel (the star of the show)In a large bowl, whisk together 3 cups of the flour, the brown sugar, 1/2 cup of the granulated sugar, 1 teaspoon of the salt, and all of the cinnamon. Melt 1 cup of the butter and pour it in. Stir until the mixture looks like wet sand with lots of big chunks — don't try to smooth it out. Those chunks are exactly what you want. Set aside.
3. Mix the dry cake ingredientsIn a separate large bowl or stand mixer, whisk together the remaining 2 1/4 cups flour, the remaining 1 1/4 cups granulated sugar, the baking powder, baking soda, and 3/4 teaspoon of the salt.
4. Cut butter into the dry mixChop 3/4 cup of the butter (softened but still cool — not melty) into chunks and add to the flour mixture along with 1/2 cup of the sour cream. Using the paddle attachment or electric beaters, blend until the butter is fully worked in and the mixture comes together. Don't overmix — just go until everything looks evenly moistened. This step builds the cake's tender crumb.
5. Whisk the wet ingredientsIn another bowl, whisk together the eggs, the remaining 1 cup sour cream, and 1 tablespoon (3 teaspoons) of the vanilla extract until smooth and well combined.
6. Combine the batterAdd the wet ingredients to the dry mixture in three additions, beating on low between each. Scrape down the bowl as needed. The batter will be thick and fluffy — a few small lumps are fine, you don't want to overmix it.
7. Layer batter and streuselSpread 2 cups of batter into the prepared pan. Sprinkle 1 cup of streusel evenly over the top, breaking up any too-large chunks with your fingers. Spread another 2 cups batter on top (this is fiddly — drop spoonfuls and gently smooth them with an offset spatula). Add another 1 cup streusel. Top with the remaining batter and spread to the edges. Add another 2 cups of streusel on top. Reserve any remaining streusel on a small plate or baking sheet — you'll use it later.
8. Bake the first roundBake at 350°F for 25 minutes. The cake will start to puff and the streusel on top will set.
9. Add the reserved streusel and finish bakingWork quickly here — open the oven, sprinkle all the reserved streusel over the top of the cake (focus on any spots where the batter has puffed through), and close the oven right away. Bake another 20–25 minutes, until a toothpick inserted in the center comes out with no wet batter. Total bake time is about 45–50 minutes. Adding the streusel halfway through is the trick to getting a crumbly, intact topping without it sinking into the cake.
10. CoolLet the cake cool on a wire rack for at least 15–20 minutes before slicing. This cake is best served warm — a quick 15-second zap in the microwave brings cooled slices right back to life.
11. Make the vanilla glazeIn a medium bowl, beat the remaining 1/4 cup butter (very soft) until smooth. Add the remaining 1 teaspoon vanilla, the remaining 1/2 teaspoon salt, the milk, and the powdered sugar. Beat until very smooth and pourable. If it's too thick, add a splash more milk; too thin, a spoonful more powdered sugar.
12. Drizzle and serveDrizzle the glaze generously over the warm cake right before serving. Slice into 16 squares and enjoy with coffee, tea, or a tall glass of milk.

Notes & Tips