For the streusel:
- 1/4 cup sugar
- 1/3 cup brown sugar
- 1 teaspoon cinnamon
- 8 tablespoons (1 stick) butter, melted
- 1 1/3 cups flour
For the cake:
- 6 tablespoons butter, at room temperature
- 3/4 cup sugar
- 2 eggs
- 1 teaspoon vanilla
- 3/4 teaspoon grated lemon zest
- 2/3 cup nonfat Greek yogurt or sour cream
- 1 1/4 cups flour
- 1 teaspoon baking powder
- 1/4 teaspoon baking soda
- 1/2 teaspoon salt
- 1 1/2 cups blueberries (or berries of your choice), fresh or frozen
Pre-heat the oven to 350°F. Butter and flour a 9-inch round baking pan.
Make the streusel: Combine the sugar, brown sugar and cinnamon in a bowl. Stir in the melted butter, then the flour. Mix well and set aside.
Make the cake: Cream the butter and sugar in the bowl of an electric mixer fitted with the paddle attachment on high speed for 4-5 minutes, until light. Reduce the speed to low and add the eggs one at a time, then add the vanilla, lemon zest, and yogurt or sour cream. In a separate bowl, sift together the flour, baking powder, baking soda and salt. With the mixer on low speed, add the flour mixture to the batter until just combined. Fold in the berries and stir with a spatula to be sure the batter is completely mixed.
Spoon the batter into the prepared pan and spread it out with a knife. With your fingers, crumble the topping evenly over the batter. Bake for 40-50 minutes, until a cake tester comes out clean.