Ashley | Baker By Nature

For the Crumb Topping:
In a medium bowl, combine the flour, both sugars, cinnamon, and salt. 
Stir in the melted butter, mixing just until combined. Set aside while you prepare the rest of the recipe. The mixture will absorb the butter as it sits and become more crumbly by the time you’re ready to use it.
For the Filling:
In a medium bowl, combine the brown sugar, cinnamon, cocoa powder, and espresso powder until evenly combined. Set aside until needed. 
For the Coffee Cake:
Preheat the oven to 350 degrees (F). Line a 9x13-inch aluminized steel or metal baking pan with aluminum foil, allowing two of the sides to overlap the pan (you’ll use these as handles later to remove the cake). then spray the pan - and foil - with nonstick baking spray. Set pan aside until needed. (Note: ceramic or glass pans will take longer to bake).
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and nutmeg, cinnamon, and espresso powder until well combined. Set aside. 
In a large liquid measuring cup, combine the sour cream and buttermilk until well combined. Set aside. 
In the bowl of a stand mixer fitted with the paddle attachment, or in a large bowl using a handheld electric mixer, beat together the butter and sugar on medium speed until light and fluffy, 3 minutes. Beat in the vanilla. 
Add in the eggs, one at a time, beating well after each addition, and scraping the sides and bottom of the bowl frequently to ensure everything is evenly combined. 
Reduce the mixer speed to low. Add the flour mixture in three additions, alternating with the sour cream/milk mixture, in two additions, beginning and ending with the flour. Do not over mix here or the cake will be dry!

Using a rubber spatula, scrape about half of the batter into the prepared pan. 

Sprinkle the filling evenly on top and gently press it down with your hands. Then scrape the remaining batter on top of the filling and spread evenly on top of the filling. If you find it hard to spread the cake batter, use a lightly greased spoon or spatula. 

Sprinkle the crumb topping evenly over the batter in the pan.

Bake for 58 to 60 minutes, or until the crumbs are golden brown and a toothpick or cake tester inserted in the center of the cake comes out clean.
Place the cake in the pan on a cooling rack and drizzle with glaze. 
Cool completely before removing from the pan, slicing in squares, and serving. Serve with coffee! 

For the Glaze:
In a medium bowl, whisk together the confectioners’ sugar and milk. Drizzle on top of cake and let set, about 5 minutes, before serving.