Preheat your oven to 350°F (175°C).
In a mixing bowl, combine the blueberries, sugar, and lemon juice.
Spread the blueberry mixture evenly in a greased baking dish.
In another bowl, mix the flour, oats, brown sugar, cinnamon, and salt.
Pour the melted butter into the dry mixture and stir until crumbly.
Evenly sprinkle the crumble topping over the blueberries.
Bake for 30-35 minutes until the topping is golden brown.
Remove from the oven and let it cool for about 10 minutes.
Serve warm, optionally with vanilla ice cream.
Enjoy your delicious homemade blueberry crumble!