Coffee Cake

Preparation

1. Step 1

   Heat the oven to 350 degrees. Grease a 9-by-13-inch pan with butter, then line the bottom with parchment paper, leaving an overhang on two sides; dust the exposed sides with flour.

2. Step 2

   Make the crumble: Combine the flour, sugar, butter, cinnamon and salt in a medium bowl. Mix well with your hands until the mixture forms crumbles (they may not be uniform in size), and set aside.

3. Step 3

   Make the cake: In the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl if you are using a hand mixer), combine the butter and sugar. Mix on medium-high speed until light and fluffy, about 3 minutes. Reduce the speed to low and add the eggs, one at a time, scraping down the sides of the bowl with a spatula after each addition. Add the vanilla extract and mix until just combined.

4. Step 4

   In a medium bowl, whisk together the flour, baking powder, baking soda and salt. With the mixer on low, gradually add the dry ingredients and the buttermilk in three parts, beginning and ending with the flour mixture. Use a spatula to make sure the batter is well mixed.

5. Step 5

   Spoon half the batter into the prepared pan, smoothing it into an even layer. Scatter 2½ cups of the crumble evenly over the cake, then sprinkle lightly with more cinnamon. Spoon the rest of the cake batter over the crumble layer in big spoonfuls. Gently spread with a spatula to cover, then top with the remaining crumble.

6. Step 6

   Bake until the crumble is browned and a toothpick inserted into the center of the cake comes out with just a few crumbs on it, 35 to 40 minutes. Cool for at least 30 minutes, then run a knife around the edges of the cake and remove it using the parchment paper overhang. Cut into squares and serve. (You can also serve the cake directly from the pan.) The cake will keep, well wrapped at room temperature, for up to 3 days.