- 2 1/2 cups cake flour
- 2 teaspoons baking powder
- 1/2 teaspoon salt
- 1/2 cup plus 2 tablespoons (1 1/4 sticks) unsalted butter, room temperature
- 1 1/2 cups sugar
- 3 tablespoons frozen orange juice concentrate, thawed
- 1 1/2 teaspoons grated orange peel
- 1 teaspoon vanilla extract
- 4 large eggs
- 1 cup whole milk
- 2 1/2-pint baskets blueberries
- 2 tablespoons sugar
- 1 teaspoon fresh lemon juice
- 1 8-ounce package cream cheese, room temperature
- 1/2 cup (1 stick) unsalted butter, room temperature
- 3 1/4 cups powdered sugar
- 2 tablespoons frozen orange juice concentrate, thawed
- 1 teaspoon grated orange peel
- 1/2 teaspoon vanilla extract
- 2 1/2-pint baskets blueberries
- Preheat oven to 350°F. Butter and flour two 9-inch-diameter cake pans with 1 1/2-inch-high sides; line bottoms with rounds of parchment paper. Sift first 3 ingredients into medium bowl. Beat butter in large bowl until fluffy. Gradually add sugar, beating until blended. Beat in concentrate, peel, and vanilla. Beat in eggs 1 at a time. Beat in flour mixture in 4 additions alternately with milk in 3 additions. Divide batter between prepared pans. Bake cakes until tester inserted into center comes out clean, about 30 minutes. Cool in pans on rack.
- Combine berries, sugar, and lemon juice in heavy small saucepan. Bring to boil over high heat, stirring until sugar dissolves. Boil until mixture is reduced to 3/4 cup, stirring occasionally and mashing berries coarsely with fork, about 8 minutes. Chill filling uncovered until cold, about 30 minutes.
- Beat cream cheese and butter in bowl to blend. Beat in powdered sugar in 4 additions, then orange concentrate, peel, and vanilla. Chill until firm but spreadable, about 30 minutes.
- Cut around cakes to loosen. Turn cakes out. Peel off parchment. Place 1 layer, flat side up, on platter. Spread filling to within 1/2 inch of edges. Chill 5 minutes. Top with second layer, flat side down. Spread 1/2 cup frosting thinly all over cake to seal. Spread remaining frosting over cake. Mound remaining blueberries on top. (Can be made 1 day ahead; chill. Serve at room temperature.)