Ingredients:

  • For the Brown Sugar Streusel Topping:
  • ¼ cups All-Purpose Flour (150g)
  • ¾ cup Light Brown Sugar, packed (150g)
  • ½ teaspoons Ground Cinnamon
  • ½ cup Unsalted Butter, very cold, cubed (113g)
  • For the Cinnamon Swirl Filling:
  • ¼ cup Granulated Sugar (50g)
  • teaspoons Ground Cinnamon
  • tablespoons Unsalted Butter, softened (28g)
  • For the Coffee Cake Batter:
  • ¼ cups All-Purpose Flour (270g)
  • tablespoon Baking Powder
  • ½ teaspoon Salt
  • cup Unsalted Butter, softened (227g)
  • ½ cups Granulated Sugar (300g)
  • Large Eggs, room temperature
  • teaspoon Vanilla Extract
  • cup Sour Cream or Full-Fat Plain Yogurt (240g)

Instructions:

  1. Preheat oven to 350°F (175°C). Grease and flour a 9x13 inch baking pan or line with parchment paper.
  2. Make the Streusel: In a medium bowl, combine flour, brown sugar, and cinnamon for the topping. Cut in the cold, cubed butter using a pastry blender or your fingertips until the mixture resembles coarse peas. Set aside in the refrigerator.
  3. Make the Swirl Mixture: In a small bowl, thoroughly mix the swirl sugar, swirl cinnamon, and softened butter until a thick, spreadable paste forms. Set aside.
  4. Combine Dry Cake Ingredients: Whisk together the cake flour, baking powder, and salt in a separate bowl.
  5. Cream Butter & Sugar: In a large bowl, cream the softened butter and granulated sugar until light and fluffy (about 3–4 minutes).
  6. Incorporate Eggs & Vanilla: Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
  7. Alternate Dry & Wet: Gently mix in half of the dry ingredients until just combined. Mix in the sour cream/yogurt. Mix in the remaining dry ingredients until just combined—do not overmix!
  8. Assemble the Layers: Pour half of the batter into the prepared pan, spreading evenly. Dot the cinnamon swirl mixture evenly over the batter. Gently use a knife or offset spatula to swirl the mixture through the batter.
  9. Top with Remaining Batter & Streusel: Carefully dollop the remaining batter over the swirl layer, spreading lightly. Sprinkle the chilled streusel evenly over the top.
  10. Bake for 45–55 minutes, or until a wooden skewer inserted near the centre comes out clean or with moist crumbs attached.
  11. Allow the cake to cool in the pan on a wire rack for at least 20 minutes before slicing and serving.