Ingredients:

  • 1/2 cup (115g) unsalted butter, softened
  • 1 cup (200g) brown sugar, packed
  • 1 1/2 cups (190g) all-purpose flour
  • 1 tbsp (8g) ground cinnamon
  • 1/4 tsp (1.5g) salt
  • 1/2 cup (115g) unsalted butter, softened
  • 1 cup (200g) granulated sugar
  • 2 large eggs, room temperature
  • 1 tsp (5ml) pure vanilla extract
  • 2 cups (250g) all-purpose flour
  • 1 tbsp (12g) baking powder
  • 1/2 tsp (3g) salt
  • 1 cup (240g) full-fat sour cream, room temperature
  • 2 medium peaches, diced into 1/2-inch pieces
  • 1 cup (150g) fresh blueberries
  • 1 tbsp (8g) all-purpose flour
  • 1 cup (120g) powdered sugar
  • 2 tbsp (30ml) whole milk
  • 1/2 tsp (2.5ml) vanilla extract

Instructions:

  1. Pre-heat your oven to 350°F (175°C). Grease a 9-inch square pan and line it with parchment paper, leaving an overhang for easy removal.
  2. Cream the softened butter and brown sugar until combined, then stir in flour, cinnamon, and salt until a sandy, clumpy texture forms. Set aside.
  3. Beat the butter and granulated sugar on medium-high until light and fluffy (about 3 minutes).
  4. Add eggs one at a time, followed by the vanilla extract, beating well after each addition.
  5. Gradually mix in the flour, baking powder, and salt on low speed until just combined.
  6. Stir in the sour cream using a spatula until the batter is smooth and velvety.
  7. In a small bowl, toss the diced peaches and blueberries in 1 tablespoon of flour until lightly coated.
  8. Gently fold the floured fruit into the batter using a spatula to avoid crushing the berries, then spread the batter evenly into the prepared pan.
  9. Sprinkle the cinnamon crumble evenly across the top, pressing very lightly.
  10. Bake for 35-40 minutes. The cake is done when a toothpick inserted into the center comes out clean and the edges are a deep mahogany-gold.
  11. Let cool in the pan for 20 minutes before transferring to a wire rack. Drizzle with the whisked glaze once the cake is completely cool.