Step 1

Preheat oven to 350 degrees. Grease an 8 inch glass square baking dish.

Step 2

To prepare the streusel, add the flour, brown sugar, cinnamon and butter to a bowl and mix with a fork until combined. Set aside.

Step 3

To make the cake batter, beat the sugar and butter until fluffy, about 3-4 minutes.

Step 4

Add the sour cream and milk, and mix well. Then add egg and vanilla extract and mix until smooth.

Step 5

Combine flour and baking powder in a separate bowl, then add the dry ingredients to the batter and mix well.

Step 6

Spread half the cake batter into the bottom of the pan. Top the batter with half the berries and half the streusel mixture, then spread the remaining cake batter over streusel.

Step 7

Sprinkle remaining berries and streusel over top of the cake batter. Bake for 40-45 minutes, until a toothpick inserted comes out clean.

Step 8

Remove cake from oven and cool for about 20 minutes before serving.