Birthday Coffee Cake

Preheat the oven to 350°F. Prepare an 8" square pan with a parchment sling or reusable silicone liner, then lightly grease the sides of the pan. Alternatively, line a 9" cake pan with a round piece of parchment or round reusable liner and lightly grease the sides.  

To make the filling: In a small bowl, combine the sugar and cocoa. Set aside. 

To make the crumbs: Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess. In a medium bowl, whisk together the flour, sugars, and salt. Add the butter and vanilla; toss to combine. Using a bowl scraper, fork, or your fingertips, work in the butter until no dry spots remain and crumbs form. The crumbs should range in size from peas to walnuts. Stir in the sprinkles; set aside.

To make the cake: In a large bowl or bowl of a stand mixer, combine the flour, sugar, baking powder, salt, and baking soda. Add the butter and mix at low speed until the mixture looks sandy, about 1 to 2 minutes. (This is known as the reverse creaming or paste method.)

Beat in the extracts and eggs, then mix until no dry spots of flour remain. Stop the mixer and scrape the bowl and beater as needed; the mixture will be thick.

Keep the mixer running and slowly add the buttermilk. Mix until smooth, then stop the mixer to scrape the bowl and mix again at medium-low speed for 1 minute; this final mix is key to ensuring the best texture so don't skip it.

Gently fold the sprinkles into the batter. 

To assemble the coffee cake: Transfer half the batter (about 2 cups, 420g) into the prepared pan, spreading it all the way to the edges. 

Sprinkle the filling evenly over the batter. 
 

Pour the remaining batter evenly over the filling and gently spread to the edges (a small offset spatula is a helpful tool here). The top layer will be thin; it’s OK if some filling gets mixed in.

Sprinkle the crumbs evenly over the batter and gently press to help them adhere. 

Bake the cake for 45 to 50 minutes, until it’s set in the middle and light brown on top. When the cake is done, a toothpick or paring knife inserted into the center should come out mostly clean. 

Remove the cake from the oven and allow it to cool in the pan for 20 minutes. While the cake is cooling, prepare the glaze. 

To make the glaze: In a small bowl, stir together the glaze ingredients until smooth, starting with the smaller amount of water. Add additional water as needed until the glaze is the consistency of molasses. 

Remove the cake from the pan using the overhanging edges of parchment as handles to gently lift it out. (If you used a silicone liner or parchment round, run a nylon spreader or dull knife around the edges of the pan to loosen the cake and then gently tip it out.) Place the cake, still on the parchment if a sling was used, on a wire rack to cool slightly.

Drizzle the glaze over the cake and garnish with additional sprinkles. Cut and serve warm or at room temperature. 

Storage information: Store leftover Birthday Coffee Cake, well wrapped, at room temperature for several days; freeze for longer storage.