Fold fresh blackberries into a buttermilk cake batter for a refreshing summertime treat.
Preheat the oven to 375°. Grease a 9-inch round cake pan with 2-inch-high sides. Line the bottom with a parchment paper round.
In a large bowl, whisk the flour, sugar, baking powder, baking soda, and salt. In a medium bowl, whisk the eggs. Whisk in the buttermilk, butter, lemon zest, and vanilla. Make a well in the center of the dry ingredients and gradually stir in the wet ingredients until almost blended. Fold in the berries. (Be careful not to overmix.) Scrape the batter into the pan.
Bake until the edges of the cake pull away from the sides of the pan and a toothpick inserted into the center comes out clean, 40 to 45 minutes. Let cool on a wire rack for 10 minutes. Invert the cake onto the rack; peel off the paper. Let cool. Before serving, dust the cake with confectioners’ sugar.