Ingredients:

  • 1 ½ cups (188g) all-purpose flour, spooned and leveled
  • ½ cup (60g) yellow cornmeal
  • 1 teaspoon baking powder
  • 1 teaspoon baking soda
  • ½ teaspoon salt
  • ½ cup (113g) unsalted butter, softened to room temperature
  • 1 cup (200g) packed light or dark brown sugar
  • 2 large eggs, at room temperature
  • 1 teaspoon pure vanilla extract
  • ⅔ cup (160ml) buttermilk, at room temperature
  • 1 peach, peeled and chopped
  • 1 cup (115g) fresh or frozen blackberries (do not thaw)
  • Optional: coarse sugar (such as Demerara) for topping
  • ¼ cup (56g) unsalted butter (½ stick or 4 Tbsp)
  • 1 ½ cups (180g) confectioners' sugar (icing sugar)
  • 3 tablespoons (45ml) milk
  • ¼ teaspoon pure vanilla extract
  • ⅛ teaspoon salt

Instructions:

  1. Preheat oven to 350°F (177°C). Butter the skillet or springform pan.
  2. Whisk together flour, cornmeal, baking powder, baking soda, and salt in a bowl. Set aside.
  3. Beat softened butter and brown sugar with an electric mixer until light and fluffy.
  4. Beat in eggs one at a time, then stir in vanilla.
  5. Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined.
  6. Gently fold in the chopped peaches and blackberries.
  7. Spread batter evenly into the prepared skillet. Sprinkle with coarse sugar, if using. Bake until a toothpick inserted into the center comes out clean.
  8. Let the cake cool slightly on a wire rack.
  9. Melt butter in a light-colored skillet over medium heat. Cook, stirring occasionally, until the butter foams, then browns and develops a nutty aroma. Remove from heat and cool slightly.
  10. Whisk the browned butter with confectioners' sugar, milk, vanilla, and salt until smooth. Adjust consistency with more sugar or milk, if needed.
  11. Drizzle the brown butter icing over the cooled cake. Slice and serve warm or at room temperature.