Blueberry Crumb Cake

Sunday at the farmers market means lots of blueberries at this time of year. I made a blueberry tart last weekend that was a big hit. This weekend I am keeping it rustic and simple, and will set aside a few blueberries to make a Blueberry Crumb Cake. This recipe is humble and homey. I blend whole wheat and white flour and use brown sugar in place of granulated sugar, lending richness and texture to the cake. Lemon zest, a no-fail partner with blueberries, lightens and brightens the flavor. Serve this cake for brunch or tea along with a pitcher of lemony iced tea.

Blueberry Crumb Cake

For the crumb topping:
1/4 cup all purpose flour
1/4 cup light brown sugar
1/4 cup granulated sugar
1/4 teaspoon salt
4 tablespoon unsalted butter, cold, in pieces

For the cake:
1 cup all-purpose flour
1 cup whole wheat flour
2 teaspoons baking powder
1/2 teaspoon salt
1/2 teaspoon ground cinnamon
1/4 teaspoon ground nutmeg
3/4 cup unsalted butter, room temperature
2/3 cup packed light brown sugar
1 teaspoon vanilla extract
1 teaspoon finely grated lemon zest
2 large eggs
1/2 cup sour cream
1 1/2 cups blueberries, divided

Preheat oven to 350 F. Butter a square baking pan.

Prepare crumb topping: Mix flour, sugars and salt in a bowl. Work butter in with fingers or pulse with a food processor to form a clumpy texture. Set aside.

Prepare cake: Mix flours, baking powder, salt, cinnamon and nutmeg together in a large bowl. Mix butter and brown sugar together in a bowl of an electric mixer until light and fluffy. Mix in vanilla and lemon zest. Whisk eggs and sour cream together in a medium bowl. Mix 1/3 dry ingredients into the butter and sugar. Mix in 1/2 of the eggs. Repeat process finishing with last 1/3 of the dry ingredients. Stir in 1 cup blueberries. Pour batter baking pan. Top with remaining blueberries. Sprinkle crumb topping over blueberries. Bake in oven until a knife inserted in center comes clean, about 1 hour. Serve warm or at room temperature. (The flavors will develop as the cake cools.)