Blueberry Crumb Cake

ingredients

For the crumbs:
8 tablespoons (1 stick) unsalted butter
1/3 cup dark brown sugar
1/4 cup sugar
2 teaspoons ground cinnamon
1/4 teaspoon salt
1 1/4 cup all-purpose flour

For the cake:
1 cup all-purpose flour
1/2 teaspoon baking soda
1/2 teaspoon baking powder
1/4 teaspoon salt
5 tablespoons unsalted butter, at room temperature
1/2 cup sugar
1 teaspoon pure vanilla extract
1 large egg, at room temperature
1/2 cup sour cream
1 cup fresh or frozen blueberries

directions

Preheat the oven to 350 degrees F. Line an 8 x 8-inch square pan with parchment paper, leaving overhang and set aside.

In a medium saucepan over low heat, combine the butter, sugars, cinnamon and salt. When the butter is melted, turn off the heat and stir in the flour. Set aside to cool.

In a large bowl, whisk together the flour, baking soda, baking powder and salt. Using an electric mixer, cream the butter and sugar together till light and fluffy. Add the vanilla, egg and sour cream, and mix till incorporated. Add the dry ingredients and mix until fully combined. Fold in the blueberries.

Transfer the batter to the prepared pan and use a spatula to spread. With your hands, form small to medium-sized balls with the crumb mixture and scatter on top of the batter. Bake in the oven till a toothpick inserted into the center comes out clean, about 45 to 55 minutes. The crumbs should be golden brown and feel firm. If they begin to look too brown, cover with a piece of foil till the cake is done.

Cool in the pan until the cake is just warm. Grasp the parchment paper with both hands and lift the cake out of the pan. Cut into 9 squares.