Ingredients:

  • 1.5 cups all-purpose flour
  • 0.5 cup white whole wheat flour
  • 2 tsp baking powder
  • 0.5 tsp salt
  • 0.5 cup honey
  • 0.5 cup unsalted butter, softened
  • 1 large egg
  • 0.5 cup plain Greek yogurt
  • 1 tsp vanilla extract
  • 2 cups fresh blueberries
  • 1 tbsp cornstarch
  • 0.5 cup rolled oats
  • 0.25 cup brown sugar
  • 0.25 cup all-purpose flour
  • 1 tsp ground cinnamon
  • 3 tbsp unsalted butter, cold and cubed

Instructions:

  1. In a small bowl, toss the fresh blueberries with cornstarch until lightly dusted. Set aside.
  2. In a medium bowl, combine both flours, baking powder, and salt.
  3. In a large bowl, beat the softened butter and honey until smooth. Add the egg and vanilla, beating until fluffy.
  4. Gradually stir in the Greek yogurt. Slowly incorporate the dry flour mixture until just combined.
  5. Pour half of the batter into a greased 9x13-inch baking pan.
  6. Scatter half of the cornstarch-coated blueberries over the batter.
  7. Spread the remaining batter over the berries, then top with the remaining blueberries, gently pressing them into the surface.
  8. Rub the cold cubed butter into the oats, brown sugar, flour, and cinnamon using fingertips until the mixture resembles coarse sand.
  9. Sprinkle the streusel evenly across the top of the cake.
  10. Bake at 350°F (175°C) for 40–45 minutes until edges are deep mahogany-brown and the center springs back when touched.