- 1⁄3 cup rolled oats
- 1⁄3 cup flour
- 1⁄4 cup sugar
- 1-1⁄4 teaspoons cinnamon
- 1⁄4 teaspoon salt
- 3 tablespoons butter, softened
- 1-2⁄3 cups flour
- 2 teaspoons baking powder
- 1⁄2 teaspoon salt
- 6 tablespoons butter, softened
- 1 cup sugar
- 2 large eggs
- 1⁄2 cup reduced-fat sour cream
- 1⁄4 cup fat-free half-and-half
- 1 teaspoon vanilla
- 2 cups fresh or frozen (not thawed) blueberries
- Preheat oven to 350°F.
- Spray a 9 x 9-inch baking pan with non-stick spray.
- Make the topping: In a small bowl, stir oats, flour, sugar, cinnamon and salt.
- Add butter and blend until crumbly. Set aside.
- Make the cake batter: In a medium bowl, stir together flour, baking powder and salt; set aside.
- In a large mixing bowl, add butter and sugar; with an electric mixer, beat until fluffy, about 1 minute.
- Add the eggs, sour cream, half-and-half and vanilla; beat until well blended, about 1 minute.
- Add the flour mixture; beat on low speed to combine, scraping the sides with a rubber spatula until blended, about 30 seconds.
- Increase speed to medium and mix just until well blended, about 30 seconds.
- With a rubber spatula, gently fold in the blueberries.
- Turn batter into prepared pan.
- Sprinkle the topping mixture evenly on top; press lightly.
- Bake until a wooden pick inserted in the center comes out clean, 40 to 45 minutes.
- Let cool in pan 30 minutes before serving.