Ingredients:

  • For the Cinnamon Streusel Topping & Filling:
  • 1 cup (125g) All-Purpose Flour
  • 1 cup (200g) Packed Light Brown Sugar
  • 1 Tbsp (15g) Ground Cinnamon
  • ½ tsp Salt
  • ½ cup (113g) Unsalted Butter, cold and cubed
  • For the Cake Batter:
  • 2 ¼ cups (280g) All-Purpose Flour, sifted
  • 1 tsp Baking Soda
  • ½ tsp Baking Powder
  • ½ tsp Salt
  • 1 cup (226g) Unsalted Butter, room temperature
  • 1 ½ cups (300g) Granulated Sugar
  • 4 large Eggs, room temperature
  • 1 ½ cups (360ml) Full Fat Sour Cream, room temperature
  • 1 tsp Vanilla Extract

Instructions:

  1. Preheat oven to 350°F (175°C). Grease and flour a standard 9x13 inch baking pan, lining the bottom with parchment paper if using.
  2. Make the Streusel: In a medium bowl, combine flour, brown sugar, cinnamon, and salt. Cut in the cold, cubed butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs. Set aside.
  3. Combine Dry Ingredients: Whisk together the sifted flour, baking soda, baking powder, and salt in a separate bowl. Set aside.
  4. Cream Butter and Sugar: In the bowl of your stand mixer, cream the room temperature butter and granulated sugar on medium speed until light and fluffy (about 3–4 minutes).
  5. Incorporate Eggs: Beat in the eggs one at a time, mixing well after each addition until just combined. Scrape down the sides of the bowl.
  6. Add Wet & Dry Alternately: Reduce mixer speed to low. Add one-third of the dry ingredients, mix briefly. Add half of the room temperature sour cream, mix briefly. Repeat the process (dry, sour cream, dry). Mix only until just combined—do not overmix! Stir in the vanilla by hand.
  7. Assemble the Layers: Spread half of the batter evenly into the prepared pan. Sprinkle half of the prepared streusel mixture evenly over this batter layer. Gently spoon the remaining batter over the streusel. Top evenly with the rest of the streusel.
  8. Bake for 50–60 minutes, or until a wooden skewer inserted into the centre comes out clean (avoiding thick pockets of streusel). If the top browns too quickly, loosely tent with foil.
  9. Cool the cake in the pan on a wire rack for at least 20 minutes before slicing.