1 1/2 cups fresh blueberries
1/2 cup butter
1 1/8 cups all-purpose flour
2 tablespoons orange juice
3/4 cup white sugar
1 egg
2 teaspoons lemon zest
1/2 cup lemon juice
1 (8 ounce) can frozen orange juice concentrate
Preheat oven to 350 degrees F (175 degrees C).
In a large bowl, mash blueberries; set aside. Place butter in a large saucepan over medium heat. Stir constantly until softened; just about melts. When butter has melted, mix in flour and sugar, then beat in orange juice and lemon zest.
Pour orange juice into prepared crust. Spread over blueberry mixture. Top with lemon peel, then top with remaining blueberry mixture. Sprinkle with orange peel.
Bake in preheated oven for 50 minutes or until toothpick inserted in center comes out clean. Cool completely before cutting into squares. Store in refrigerator.