PREPARATION

1. First, make the topping:
2. In a large saucepan over medium-high heat, add 2 cups of the blueberries, both sugars, and mix until sugar has dissolved.
3. In a small bowl, stir the cornstarch into the 1 tablespoon cold water, then pour into the blueberry mixture. Stir until thickened.
4. Add lemon zest, stir to combine, and remove from heat. Stir in remaining blueberries. Transfer to a bowl and let cool 5 minutes before transferring to the fridge to cool completely.
5. While blueberry topping chills, make the crust:
6. Preheat oven to 325°F and grease a 9×13-inch baking dish with nonstick spray.
7. In a medium bowl, stir together the melted butter, flour, and chopped pecans until well combined. Press mixture evenly in bottom of prepared baking dish.
8. Bake crust for 15 minutes. Remove from oven and let cool while you make the filling.