Blueberry Lemon Crumble Cake

The streusel used here is also available as a standalone recipe: Streusel Topping (Blueberry Lemon Crumble Cake).

The sauce used here is also available as a standalone recipe: Blueberry Sauce.

Ingredients

Cake

• 3/4 cup (180 ml) unsalted butter, softened
• 1 cup (240 ml) sugar
• 2 large eggs
• 1 teaspoon (5 ml) vanilla extract
• 2 teaspoons (10 ml) lemon juice
• 2 cups (480 ml) all-purpose flour
• 1 teaspoon (5 ml) baking powder
• 1 teaspoon (5 ml) baking soda
• 1/2 teaspoon (2.5 ml) salt
• 2 cups (480 ml) fresh blueberries
• 1 1/2 cups (360 ml) sour cream

Streusel Topping

• 1/4 cup (60 ml) white sugar
• 1/4 cup (60 ml) brown sugar
• 1 cup (240 ml) all-purpose flour
• 1 1/2 teaspoons (7.5 ml) cinnamon
• 1/2 cup (120 ml) unsalted butter, chilled

Blueberry Sauce

• 2 cups (480 ml) blueberries
• 1/2 cup (120 ml) granulated sugar
• 1 tablespoon (15 ml) cornstarch
• 1/2 vanilla bean, seeded
• 2 teaspoons (10 ml) lemon juice

Method

1. To make the cake, preheat the oven to 350 degrees F (175°C). Grease and flour a 10-inch (25 cm) tube pan.
2. Cream the butter and sugar in a large mixing bowl until light and fluffy. Add the eggs, one at a time, beating well after each addition. Add the vanilla extract and lemon juice. Beat very well.
3. Combine the flour, baking soda, baking powder, and salt in a separate bowl. Alternately add the dry ingredients and the sour cream into the butter mixture. *Begin and end with the dry ingredients. Mix well.
4. Gently fold in the blueberries.
5. To make the streusel, combine the sugars, flour, and cinnamon in a bowl. Cut in the chilled butter with a pastry blender until the mixture resembles coarse crumbs. You can also use an electric mixer with a paddle attachment. You will have some extra streusel--keep in freezer for quick fruit tart another day!
6. To assemble and bake, spread half of the batter into the prepared pan. Sprinkle with a layer of the streusel. Top with the remaining batter, then top with another layer of streusel.
7. Bake for approximately 55 minutes. The cake will be done when golden brown, the sides of the cake pull away slightly from the edge of the pan, and a toothpick inserted in the center comes out clean.
8. Remove the pan from the oven and cool on a rack for 45 minutes. Unmold onto the rack streusel side down and allow to cool completely. Then invert, streusel side up, onto a cake plate. Serve dusted with confectioners sugar or with blueberry sauce.
9. To make the sauce, add the blueberries, sugar mixed with cornstarch, vanilla bean seeds, and lemon juice to a saucepan over medium low heat. Heat to a boil, stirring occasionally. Cool completely. Serve with cake, over ice cream.