Easy Three-Berry Crumble Slab Pie

1 . Stage

Preheat the oven to 375 degrees F (190 degrees C).

2 . Stage

Lightly dust an 11x15-inch half-sheet pan with flour. Carefully place the 2 pie crusts into the bottom of the sheet pan, gently stretching and trimming the crusts to fit the bottom and up the sides of the pan.

3 . Stage

Combine berries, sugar, arrowroot powder, and salt in a large bowl; stir well.

4 . Stage

Combine oats, flour, brown sugar, apple pie spice, and salt in a medium bowl. Use a pastry knife to cut butter into the oat mixture until butter is evenly distributed throughout and the crumble topping mixture resembles small, uneven pieces.

5 . Stage

Pour berry mixture evenly onto the crust and add crumble mixture on top.

6 . Stage

Bake in the preheated oven until brown and bubbly, 45 to 55 minutes. Remove and allow to cool for 30 to 45 minutes