- 2 cups all purpose flour
- 1 cup old-fashioned oats
- 1 cup (packed) golden brown sugar
- 1/2 teaspoon salt
- 1/4 teaspoon ground cinnamon
- 1 cup (2 sticks) chilled unsalted butter, cut into 1/2-inch cubes
- 3 cups fresh blueberries (about 15 ounces) or one 12-ounce package frozen blueberries (do not thaw)
- 1 cup blueberry preserves (10 to 11 ounces)
- 1 tablespoon all purpose flour
- 1 teaspoon finely grated lemon peel
for the crust
- Preheat oven to 375°F. Butter bottom of 13x9x2-inch metal baking pan. Whisk flour, oats, sugar, salt, and cinnamon in large bowl. Add 1 cup butter; rub in with fingertips until mixture sticks together in small clumps. Transfer 2 cups to medium bowl; reserve for topping.
- Press remaining crumb mixture evenly onto bottom of prepared pan. Bake crust until golden and just firm to touch, about 22 minutes. Cool 10 minutes.
for the filling
- Mix all ingredients in medium bowl. Spread evenly over crust in pan, then sprinkle reserved topping over.
- Bake bars until filling bubbles thickly at edges and topping is golden brown, about 40 minutes; cool in pan on rack. Cut lengthwise into 4 strips, then cut each strip into 6 pieces, forming 24 bars.