My mom called this a 24 hour cake after she tasted a bite. “It won’t last 24 hours in this house!” It would be nice to find at least some crumbs tomorrow morning to accompany a cup of tea but it doesn’t seem likely.
The cake tastes like something from a gourmet bakery but it’s easy enough for a novice cook to prepare. The prep time is only 20 minutes. PS – when you buy the buttermilk and open the container, don’t be misled into thinking it’s spoiled when it pours out like watery yogurt and tastes a little sour. It’s supposed to be that way.
4 tablespoons unsalted butter, softened, plus more for greasing
1 cup all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon salt
2/3 cup plus 1 1/2 tablespoons sugar
1 large egg, at room temperature
1 teaspoon pure vanilla extract
1/2 cup buttermilk, at room temperature
1 1/4 cups blackberries, plus more for serving
Sweetened whipped cream, for serving
Preheat the oven to 400°. Butter a 9-inch round cake pan and line the bottom with parchment paper. Butter the parchment.
In a small bowl, whisk the flour, baking powder, baking soda and salt. In a large bowl, using a handheld electric mixer, beat the butter with 2/3 cup of the sugar at medium-high speed until fluffy, 3 minutes. Beat in the egg and vanilla. At low speed, beat in the buttermilk and dry ingredients in 3 alternating batches, ending with the dry ingredients; do not overbeat. Gently fold the batter just until blended, then scrape into the pan; smooth the top.
Scatter the 1 1/4 cups of blackberries over the batter; lightly press them in. Sprinkle the remaining 1 1/2 tablespoons of sugar over the cake. Bake for about 30 minutes, until a cake tester inserted in the center comes out clean.
Transfer the cake to a rack to cool for 10 minutes, then turn out the cake and remove the paper. Turn the cake right side up and let cool completely. Serve the buttermilk cake with whipped cream and more blackberries.