Instructions
Preheat the Oven
Set your oven to 350°F (175°C) and lightly grease a 9×13-inch baking dish.
Cream Butter and Sugar
In a large bowl, beat the softened butter and granulated sugar together until the mixture is light and fluffy.
Add Eggs
Mix in the eggs one at a time, beating well after each addition.
Blend in Sour Cream and Vanilla
Stir in the sour cream and vanilla until the mixture is smooth and creamy.
Combine Dry Ingredients
In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.
Create the Batter
Slowly add the dry ingredients to the wet mixture, mixing just until a smooth batter forms.
Add Blueberries
Carefully fold in the blueberries, trying not to break them up.
Prepare the Streusel
In a small bowl, mix the brown sugar and cinnamon together to make the streusel topping.
Assemble the Cake
Spread half of the batter into the prepared pan. Sprinkle with half of the streusel mixture.
Add Remaining Layers
Spoon the rest of the batter on top and spread evenly. Finish by sprinkling the remaining streusel over the top.
Bake
Place the pan in the oven and bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean.
Cool and Serve
Let the cake cool slightly before slicing. Serve warm with your favorite coffee or tea.
