Cinnamon Streusel Coffee Cake

Streusel topping

• 1 cup granulated sugar

• 1/4 teaspoon salt

• 1 cup all purpose flour

• 1 tablespoon cinnamon

• 6 tablespoons unsalted butter, melted

Filling

• 1 cup brown sugar, packed

• 1 1/2 tablespoons cinnamon

• 1 teaspoon unsweetened cocoa powder

Cake

• 12 tablespoons unsalted butter, at room temperature

• 1 teaspoon salt

• 1 1/2 cups granulated sugar

• 1/3 cup brown sugar, packed

• 2 1/2 teaspoons baking powder

• 2 teaspoons vanilla extract

• 3 large eggs, at room temperature

• 3/4 cup plain Greek yogurt, at room temperature

• 1 1/4 cups whole milk, at room temperature

• 3 3/4 cups all purpose flour
  

Preheat the oven to 350°F. Lightly grease a 9" x 13" pan.

Make the topping by whisking together the sugar, salt, flour, and cinnamon. Add the melted butter, stirring until well combined. Set the topping aside.

Make the filling by mixing together the brown sugar, cinnamon, and cocoa powder. Set it aside.

To make the cake, in a large bowl, beat together the butter, salt, sugars, baking powder, and vanilla until well combined and smooth.

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

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

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

Pour/spread half the batter (about 3 cups) into the prepared pan, spreading all the way to the edges.

Sprinkle the filling evenly on the batter.

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.

Sprinkle the topping over the batter in the pan.

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. When pressed gently in the middle, the cake should spring back.

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