Ingredients:

  • 3 cups (360 g) All-Purpose Flour, sifted
  • 1 ½ cups (300 g) Granulated Sugar
  • 1 tablespoon (15 g) Baking Powder
  • ½ teaspoon (3 g) Baking Soda
  • ½ teaspoon (3 g) Fine Sea Salt
  • 1 cup (2 sticks / 225 g) Unsalted Butter, softened (for cake)
  • 4 Large Eggs, room temperature
  • 1 tablespoon (15 ml) Vanilla Extract (for cake)
  • 1 ½ cups (360 g) Full-Fat Sour Cream, room temperature
  • ½ cup (110 g) Packed Light Brown Sugar (for swirl)
  • 2 teaspoons (10 g) Ground Cinnamon (for swirl)
  • ¼ cup (4 tablespoons / 55 g) Unsalted Butter, melted and cooled (for swirl)
  • 2 cups (240 g) Powdered Sugar (Icing Sugar), sifted (for glaze)
  • 4 – 5 tablespoons (60 – 75 ml) Whole Milk or Heavy Cream (for glaze)
  • 1 teaspoon (5 ml) Vanilla Extract (for glaze)

Instructions:

  1. Preheat the oven to 350°F (175°C). Grease and flour the 13x9 inch baking pan thoroughly, or line it with parchment paper.
  2. In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
  3. In the bowl of an electric mixer, cream the softened butter and granulated sugar on medium speed until light and fluffy (about 3-4 minutes). Scrape down the bowl.
  4. Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract.
  5. Reduce speed to low. Gradually add the dry ingredient mixture alternately with the sour cream, beginning and ending with the dry ingredients. Mix only until just combined; do not overmix the batter.
  6. In a small bowl, whisk together the brown sugar, cinnamon, and melted butter until it resembles wet sand (the swirl filling).
  7. Spread half of the cake batter evenly into the prepared pan.
  8. Sprinkle the cinnamon-sugar swirl mixture evenly over the batter layer.
  9. Carefully spoon the remaining cake batter over the cinnamon layer, ensuring the cinnamon mixture is completely covered (use a gentle spreading motion).
  10. Bake for 40–45 minutes, or until a wooden toothpick inserted near the centre comes out clean.
  11. Remove the cake from the oven and let it cool in the pan on a wire rack for 10 minutes.
  12. While the cake cools, prepare the glaze: whisk together the sifted powdered sugar, vanilla extract, and 4 tablespoons of milk/cream until smooth. Add the remaining milk/cream, one teaspoon at a time, until the glaze is thick but pourable.
  13. While the cake is still warm, pour the glaze evenly over the top, letting it drip down the edges.
  14. Allow the glaze to set for another 5 minutes before slicing and serving.