Ingredients:

  • 1/2 cup All-Purpose Flour (for streusel)
  • 1/4 cup, packed Light Brown Sugar (for streusel)
  • 1/4 cup Granulated Sugar (for streusel)
  • 1/2 teaspoon Ground Cinnamon
  • 4 tablespoons Cold Unsalted Butter, cut into 1/2-inch cubes (for streusel)
  • 1/4 cup Sliced or Flaked Almonds
  • Pinch Fine Sea Salt (for streusel)
  • 1 3/4 cups All-Purpose Flour (for cake batter)
  • 1 teaspoon Baking Powder
  • 1/2 teaspoon Fine Sea Salt (for cake batter)
  • 1/2 cup (1 stick) Unsalted Butter, softened
  • 3/4 cup Granulated Sugar (for cake batter)
  • Zest of 1 large lemon
  • 2 Large Eggs, room temperature
  • 1/2 cup Plain Greek Yogurt or Sour Cream
  • 1 tablespoon Fresh Lemon Juice
  • 1 1/2 cups Fresh Blueberries
  • 1 teaspoon All-Purpose Flour (for coating berries)

Instructions:

  1. Preheat the oven to 350°F (175°C). Grease and line your 9-inch square or round pan with parchment paper, allowing an overhang 'sling' for easy removal.
  2. In a medium bowl, whisk together the streusel dry ingredients (flour, sugars, cinnamon, salt, and almonds). Add the cold, cubed butter. Using your fingertips or a pastry blender, cut the butter into the dry ingredients until the mixture resembles coarse crumbs. Chill the streusel in the refrigerator while preparing the batter.
  3. Gently toss the 1 1/2 cups of blueberries with the 1 teaspoon of flour in a small bowl. This step prevents the berries from sinking.
  4. Whisk together the 1 3/4 cups flour, baking powder, and salt in a separate medium bowl. Set aside.
  5. In the bowl of an electric mixer, beat the softened butter, granulated sugar, and lemon zest on medium speed until the mixture is pale and fluffy—about 3 to 4 minutes. Stop and scrape down the sides frequently.
  6. Beat in the eggs, one at a time. Mix in the Greek yogurt (or sour cream) and lemon juice until just combined.
  7. Reduce the mixer speed to low. Gradually add the reserved dry ingredients, mixing only until just combined and no streaks of dry flour remain. Do not overmix.
  8. Gently fold the floured blueberries into the cake batter using a rubber spatula.
  9. Scrape the batter into the prepared baking pan, spreading it evenly. Retrieve the chilled streusel and crumble it evenly over the top. Bake for 50 to 60 minutes, or until a wooden skewer inserted into the centre comes out clean. If the top browns too quickly, tent loosely with foil.
  10. Let the cake cool in the pan for 15 minutes before using the parchment sling to lift it onto a wire rack. Serve warm or at room temperature.