Easy Blueberry Crumble Bar Recipe

0 Preheat the oven to 350 F and line a 9x9 pan with parchment paper.
1 In a large bowl, whisk together the flour, oats, brown sugar, and salt.
2 Add the butter to the flour mixture and cut it in with a fork, or work the mixture with your hands. Once the mixture takes on a sand-like texture, mix in the egg until fully combined.
3 Add the blueberries to a saucepan along with the lemon juice and sugar, then let cook over medium heat for about 10 minutes, until the blueberries have burst.
4 Whisk the cornstarch with two tablespoons water, then pour it into the blueberry mixture. Once the mixture boils and thickens, remove it from heat.
5 Press half of the crust mixture into the bottom of the pan, then pour the blueberries over top. Crumble the rest of the mixture over the blueberries.
6 Bake for 35-40 minutes, until the crust has browned. Let cool, then slice and serve.