Ingredients:

  • 1/2 cup (115g) unsalted butter, cold and cubed
  • 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
  • 1 tsp (5ml) vanilla extract
  • 8 oz (225g) sour cream, room temperature
  • 2 cups (250g) all-purpose flour
  • 1 tsp (5g) baking powder
  • 1/2 tsp (3g) baking soda
  • 1/4 tsp (1.5g) salt
  • 2 cups (300g) fresh peaches, peeled and diced into 1/2-inch pieces
  • 1 tbsp (8g) lemon juice
  • 1 tbsp (8g) granulated sugar

Instructions:

  1. Preheat oven to 325°F (165°C) and grease a 9x13-inch baking pan with butter or parchment paper.
  2. In a small bowl, combine 190g flour, 200g brown sugar, cinnamon, and 1.5g salt. Use a pastry cutter or fork to work in the 115g cold cubed butter until the mixture resembles coarse wet sand with pea-sized lumps. Place in the fridge until needed.
  3. In a large bowl, cream 115g softened butter and 200g granulated sugar until pale yellow and fluffy.
  4. Beat in eggs one at a time, then stir in vanilla extract and sour cream.
  5. Slowly fold in 250g flour, baking powder, baking soda, and 1.5g salt using a spatula until just combined.
  6. Spread half of the batter into the prepared pan.
  7. Toss diced peaches with lemon juice and 8g granulated sugar, then distribute evenly over the bottom batter layer.
  8. Top with the remaining batter, smoothing the surface with a spatula.
  9. Sprinkle the chilled cinnamon streusel generously over the top.
  10. Bake for 50–55 minutes, or until a toothpick inserted into the center comes out clean.