Preheat your oven to 350 degrees F.
In a baking dish, toss together the blueberries, lemon juice, lemon zest, granulated sugar, and cornstarch.
In a large bowl, mix the flour, oats, brown sugar, and cold butter until you have a chunky crumble.
Sprinkle the crumble evenly over the blueberry mixture.
Bake for 30 minutes or until the oat topping is a gorgeous golden brown, and the blueberries are soft and slightly oozing.
Serve it up warm with a generous scoop of ice cream!
If you have any leftovers, store them in an airtight container in the fridge for up to three days.
Enjoy the burst of blueberry goodness and crunchy crumble – the perfect way to sweeten up your Memorial Day weekend!