Ingredients:

  • 1/2 cup (65g) all-purpose flour
  • 1/4 cup (25g) rolled oats
  • 1/3 cup (65g) coconut sugar
  • 1 tsp ground cinnamon
  • 1/4 cup (56g) unsalted butter, cold and cubed
  • 2 cups (250g) all-purpose flour
  • 1 tsp baking powder
  • 1/2 tsp baking soda
  • 1/2 tsp sea salt
  • 1/2 cup (113g) unsalted butter, softened
  • 1/2 cup (100g) cane sugar
  • 2 large eggs, room temperature
  • 1 cup (240g) full-fat sour cream
  • 1 tsp pure vanilla extract
  • 1 tsp lemon zest
  • 2 cups (300g) fresh blueberries

Instructions:

  1. Preheat your oven to 180°C (350°F). Grease your 9 inch pan thoroughly and line the bottom with parchment. Note: Parchment is non negotiable for a clean release.
  2. Build the streusel. In a medium bowl, combine 65g flour, oats, coconut sugar, and cinnamon. Cut in the 56g cold cubed butter using a pastry cutter until you see pea sized crumbs.
  3. Chill the topping. Place the streusel in the refrigerator immediately. Note: Keeping the butter cold prevents it from melting into the batter prematurely.
  4. Cream the fats. In a large bowl, beat the 113g softened butter and cane sugar for 3 minutes until pale and aerated.
  5. Emulsify the eggs. Add eggs one at a time, beating well. Stir in the vanilla and lemon zest. The zest adds a bright note that cuts through the richness of the sour cream.
  6. Whisk dry ingredients. In a separate bowl, combine 250g flour, baking powder, baking soda, and sea salt.
  7. The folding dance. Alternately fold the dry ingredients and 240g sour cream into the butter mixture. Start and end with flour until no white streaks remain.
  8. Gently fold in the fresh blueberries.
  9. Spread the batter into the prepared pan and sprinkle the streusel topping over it.
  10. Bake for 50 minutes, or until a skewer inserted into the center comes out clean. Let cool for 15 minutes before serving.