Ingredients:

  • 1 cup All-Purpose Flour (for swirl)
  • 1/2 cup packed Light Brown Sugar (for swirl)
  • 2 teaspoons Ground Cinnamon (for swirl)
  • 4 tablespoons cold Unsalted Butter, cubed (for swirl)
  • 2 1/2 cups All-Purpose Flour (for batter)
  • 1 1/2 cups Granulated Sugar (for batter)
  • 2 teaspoons Baking Powder (for batter)
  • 1/2 teaspoon Salt (for batter)
  • 1 cup (2 sticks) Unsalted Butter, softened (for batter)
  • 3 Large Eggs (room temperature)
  • 1 cup Sour Cream or Full-Fat Plain Yogurt (room temperature)
  • 1 tablespoon Vanilla Extract
  • 1 cup Powdered Sugar (for optional glaze)
  • 2-3 tablespoons Milk or Cream (for optional glaze)

Instructions:

  1. Preheat oven to 350°F (175°C). Grease and lightly flour a 9x13 inch baking pan.
  2. Make the Crumbly Cinnamon Swirl (Group A): Combine 1 cup flour, brown sugar, and cinnamon in a small bowl. Cut in the cold butter using your fingertips or a pastry blender until the mixture resembles coarse crumbs. Set aside.
  3. Combine Dry Ingredients (Group B): Whisk together the remaining 2 1/2 cups flour, granulated sugar, baking powder, and salt in a large bowl.
  4. Cream Butter and Wet Ingredients: In a separate bowl, beat the softened butter until light and creamy. Beat in eggs one at a time. Mix in vanilla extract.
  5. Alternate Wet and Dry: Gently fold the dry mixture into the wet ingredients in three additions, alternating with the sour cream (start and end with dry). Mix just until combined; do not overmix.
  6. Layer the Cake: Spread half of the cake batter evenly into the prepared pan. Sprinkle half of the Cinnamon Swirl mixture over the batter. Gently dollop the remaining batter on top, then sprinkle with the remaining Cinnamon Swirl mixture.
  7. Create the Swirl: Insert a thin butter knife or skewer into the batter and gently cut back and forth in a serpentine (S-shape) pattern across the surface to create the swirl effect. Do not plunge too deep.
  8. Bake for 45–55 minutes, or until a wooden skewer inserted near the centre comes out clean or with moist crumbs attached.
  9. Cool the cake in the pan on a wire rack for 20 minutes before slicing and serving.
  10. Optional Glaze: Whisk powdered sugar and milk/cream (starting with 2 tablespoons) until smooth. Drizzle over the slightly warm or fully cooled Cinnamon Swirl Coffee Cake.