Cinnamon Streusel Coffee Cake

This recipe comes from the King Arthur Baking Company  website; I made it for Christmas this year (2025), and it turned out great. It's quite sweet, so you'll want a cup of coffee to go with it.

Ingredients

Topping

• 1 cup (198g) granulated sugar

• 1/4 teaspoon table salt, (if you use unsalted butter)

• 1 cup (120g) Unbleached All-Purpose Flour

• 1 tablespoon cinnamon

• 6 tablespoons (85g) butter, melted

Filling

• 1 cup (213g) dark brown sugar or light brown sugar, packed  [I used dark brown sugar.]

• 1 1/2 tablespoons cinnamon

• 1 teaspoon unsweetened cocoa, Dutch-process or natural (optional)

Cake

• 12 tablespoons (170g) butter, at room temperature, at least 65°F

• 1 teaspoon table salt, (1 1/4 teaspoons if you use unsalted butter)

• 1 1/2 cups (298g) granulated sugar

• 1/3 cup (71g) light brown sugar or dark brown sugar, packed  [I used dark brown sugar.]

• 2 1/2 teaspoons baking powder

• 2 teaspoons Pure Vanilla Extract

• 3 large eggs, at room temperature

• 3/4 cup (170g) sour cream or plain yogurt, at room temperature  [I used sour cream.]

• 1 1/4 cups (283g) milk, anything from skim to whole, at room temperature

Instructions

1. Preheat the oven to 350°F. Lightly grease a 9" x 13" pan, or two 9" round cake pans.

2. To make the topping: Whisk together the sugar, salt, flour, and cinnamon. Add the melted butter, stirring until well combined. Set the topping aside.

3. To make the filling: Mix together the brown sugar, cinnamon, and cocoa powder. (The cocoa powder is used strictly for color, not flavor; leave it out if you like.) Set it aside.

4. To make the cake: In a large bowl, beat together the butter, salt, sugars, baking powder, and vanilla until well combined and smooth. Note: I added the baking powder to the flour instead of adding it in this step.

5. Add the eggs one at a time, beating well after each addition.

6. In a separate bowl, whisk together the sour cream or yogurt and milk till well combined. You don't need to whisk out all the lumps.

7. Add the flour to the butter mixture alternately with the milk/sour cream mixture, beating gently to combine.

8. Pour/spread half the batter (a scant 3 cups) into the prepared pan(s), spreading all the way to the edges. If you're using two 9" round pans, spread 1 1/3 cups batter in each pan.

9. Sprinkle the filling evenly on the batter.

10. Spread the remaining batter atop the filling. Use a table knife to gently swirl the filling into the batter, as though you were making a marble cake. Don't combine filling and batter thoroughly; just swirl the filling through the batter.

11. Sprinkle the topping over the batter in the pan.

12. Bake the cake until it's a dark golden brown around the edges; medium-golden with no light patches showing on top, and a toothpick or cake tester inserted into the center comes out clean, about 55 to 60 minutes for the 9" x 13" pan, 50 to 55 minutes for the 9" round pans. When pressed gently in the middle, the cake should spring back.

13. Remove the cake from the oven and allow it to cool for 20 minutes before cutting and serving. Serve cake right from the pan.

14. Storage information: Store leftover cinnamon streusel coffee cake, well wrapped, at room temperature for several days; freeze for longer storage.