Though Danish-style coffee cakes are very close to my heart, I must confess that there’s nothing like the comfort of a piece of simple “crumb” cake with a nice hot cup in the morning. Make this exactly as you would a layer of butter cake. The formula is:
7 ounces (1 1/3 cups) all-purpose flour
7 ounces (1 cup) sugar
1 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
4 ounces (1 stick) unsalted butter, soft
6 ounces (3/4 cup) buttermilk, room-temperature
1 teaspoon vanilla
4 egg yolks, room-temperature
About 1 cup streusel for topping
Preheat your oven to 350. Combine the flour, sugar, leavening and salt in the bowl of a mixer and whisk or stir to combine. Add the butter and stir on low until the butter is completely incorporated. Meanwhile, combine the yolks with about 1/4 cup of the buttermilk and the vanilla and stir to combine them. Add the remaining buttermilk to the dry ingredients and beat on medium speed for about a minute until smooth. Scrape the bowl and beat for an additional 15-20 seconds. Add the egg mixture in thirds, beating for about 15 seconds after each addition, and scraping down the bowl as needed.
Scrape the mixture into a parchment-lined 9″ springform pan. Sprinkle the streusel evenly over the top, and bake for about an hour, until a sharp knife or cake tester inserted into the center of the cake comes out clean. Allow the cake to cool completely before slicing.