Method
- Preheat your oven to 350°F (175°C) and grease a 9x9-inch baking pan.
- Prepare the streusel topping by combining brown sugar, cinnamon, and flour in a bowl. Stir in melted butter until crumbly.
- In a large bowl, cream together softened butter and granulated sugar until light and fluffy.
- Add eggs one at a time, beating well after each addition, then mix in vanilla extract.
- In a separate bowl, whisk together flour, baking powder, baking soda, and salt.
- Gradually add dry ingredients to the butter mixture, alternating with sour cream, mixing until just combined.
- Pour half of the batter into the prepared pan, sprinkle half of the streusel topping, then add the remaining batter and top with the remaining streusel.
- Bake for 40-45 minutes or until a toothpick comes out clean. Let cool for at least 15 minutes before serving.
Notes
Ensure all ingredients are at room temperature for best results. Measure flour correctly to avoid a dry cake. Store leftovers covered at room temperature for up to 3 days.