• Preheat oven to 375°F.

To prepare the topping:

• In the bowl of a food processor combine the flour, sugars and butter. Pulse until combined and starting to form a dough. Remove the mixture to a small mixing bowl and using the back of a large spoon, press some of the topping together to form large chunks. Refrigerate until needed.

To prepare the blueberries:

• Lightly grease an 8 or 9-inch baking pan, casserole dish or deep dish pie plate. If preferred use a combination of smaller pans.
• Pour the blueberries into the prepared pan(s).
• In a small bowl whisk together ½ cup granulated sugar, cornstarch, cinnamon and lemon zest until combined. Pour the mixture over the blueberries and toss to combine. Drizzle the lemon juice over the blueberry mixture and stir gently to coat.
• Crumble the topping over the blueberries leaving some large clumps. Sprinkle the topping with the remaining 1 tablespoon granulated sugar. Bake until the berries are bubbling and the topping is golden brown, about 45-50 minutes. Tent with foil while baking if browning too quickly. Allow the crisp to cool for 15 minutes. Serve warm topped with vanilla ice cream or whipped cream spooned on individual servings.