Blueberry Bars

Name: Blueberry Bars
Prep time: 20 min
Cook time: 1 h
Total time: 1 h 30 min
Yield: 9 bars
Ingredients: Ingredients; Filling; 3 cups fresh blueberries (or 2 1/2 cups if using frozen); 1/2 cup granulated sugar; 3 tablespoons cornstarch; 1 tablespoon fresh lemon juice; 1 teaspoon lemon zest; 1/4 teaspoon vanilla extract; Pinch of salt; 2 cups all-purpose flour; 1/2 cup granulated sugar; 1/4 teaspoon salt; 1/2 cup cold unsalted butter, cubed; 1 large egg yolk; 2-3 tablespoons cold water; Streusel Topping; 1/2 cup all-purpose flour; 1/3 cup brown sugar, packed; 1/4 cup rolled oats; 1/4 teaspoon cinnamon; 3 tablespoons cold unsalted butter, cubed