While crumb cake might be too ordinary for most to request on their birthday, it was the perfect choice for my frosting-loathing and spice-loving Astronomer. To up the celebratory quotient, I swapped out traditional cinnamon for a heaping teaspoon of Guatemalan cardamom—it’s the birthday boy’s current obsession.
I knew this America’s Test Kitchen recipe would yield a winning cake, but The Astronomer’s reaction was even better than expected. Don’t tell his mama, but he declared it to be “the best birthday cake ever!” Oh, how will I ever top this in the future?
Employing cake flour in both the crumb topping and cake resulted in a delicate body and a satisfying crumb. Rich buttery notes tied everything together, while the cardamom added a sexy touch like only it can.
Although I initially frowned upon The Astronomer’s desire for a such a pedestrian cake, this one made me a crumb cake convert, and I wouldn’t hesitate to request it for my next birthday. Mmm, cardamom!
For crumb topping
- 1/3 cup (2.3 ounces) granulated sugar
- 1/3 cup packed (2.3 ounces) dark brown sugar
- 1 teaspoon ground cardamom
- 1/8 teaspoon salt
- 8 tablespoons (1 stick) unsalted butter, melted and cooled
- 1 3/4 cups (7 ounces) cake flour
- 1 1/4 cups (5 ounces) cake flour
- 1/2 cup (3.5 ounces) granulated sugar
- 1/4 teaspoon baking soda
- 1/4 teaspoon salt
- 6 tablespoons (3/4 stick) unsalted butter, cut into 6 pieces and softened
- 1 large egg, room temperature
- 1 large egg yolk, room temperature
- 1 teaspoon vanilla extract
- 1/3 cup buttermilk, room temperature
- Confectioners’ sugar, for dusting
Whisk the granulated and brown sugars, cardamom, salt, and melted butter together in a medium bowl to combine. Stir in the flour until the mixture resembles a thick, cohesive dough. Let the crumb topping mixture rest at room temperature until needed.
Adjust an oven rack to the middle position and heat the oven to 325 degrees. Line an 8-inch square baking pan with a foil sling and grease the foil.
Whisk the flour, granulated sugar, baking soda, and salt together in a large bowl. Using an electric mixer on medium-low speed, beat the butter into the flour mixture, one piece at a time, about 30 seconds. Continue to beat the mixture until it resembles moist crumbs, 1 to 3 minutes.
Beat in the egg, egg yolk, and vanilla until combined, about 30 seconds. Beat in the buttermilk until combined, about 30 seconds. Increase the mixer speed to medium and beat the batter until smooth and fluffy, about 1 minute.
Give the batter a final stir with a rubber spatula to make sure it is thoroughly combined. Scrape the batter into the prepared pan, smooth the top, and gently tap the pan on the counter to settle the batter.
Break apart the crumb topping mixture into large pea-sized pieces and sprinkle it in an even layer over the batter.
Bake the cake until the crumbs are golden and a toothpick inserted in the center of the cake comes out with a few moist crumbs attached, 35 to 40 minutes, rotating the pan halfway through baking.
Let the cake cool slightly in the pan, about 30 minutes. If desired, remove the cake from the pan using the foil, then dust with confectioners’ sugar before serving.
Serves 9 or one ecstatic Astronomer.