Barefoot Contessa's Blueberry Crumb Cake

From Barefoot Contessa at Home, 2006.

• Ready In: 1 hr 15 mins
• Serves: 6-8

Ingredients

• Streusel

• 1⁄4 cup granulated sugar
• 1⁄3 cup light brown sugar, lightly packed
• 1  teaspoon ground cinnamon
• 1⁄8 teaspoon ground nutmeg
• 1⁄4 lb unsalted butter, melted
• 1 1⁄3 cups all-purpose flour

• For the cake

• 6  tablespoons unsalted butter, at room temperature
• 3⁄4 cup granulated sugar
• 2  extra-large eggs, at room temperature
• 1  teaspoon pure vanilla extract
• 1⁄2 teaspoon  grated lemon zest
• 2⁄3 cup sour cream
• 1 1⁄4 cups all-purpose flour
• 1  teaspoon baking powder
• 1⁄4 teaspoon baking soda
• 1⁄2 teaspoon kosher salt
• 1  cup fresh blueberries
•  confectioners' sugar, for sprinkling

Directions

1. Preheat the oven to 350 degrees.
2. Butter and flour a 10-inch round baking pan.
3. For the streusel, combine the granulated sugar, brown sugar, cinnamon, and nutmeg in a bowl.
4. Stir in the melted butter and then the flour.
5. Mix well and set aside.
6. For the cake, cream the butter and sugar in the bowl of an electric mixer fitted with the paddle attachment on high speed for 4 to 5 minutes, until light.
7. Reduce the speed to low and add the eggs one at a time, then add the vanilla, lemon zest, and sour cream.
8. 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 blueberries and stir with a spatula to be sure the batter is completely mixed.
9. Spoon the batter into the prepared pan and spread it out with a knife.
10. With your fingers, crumble the topping evenly over the batter.
11. Bake for 40 to 50 minutes, until a cake tester comes out clean.
12. Cool completely and serve sprinkled with confectioners' sugar.