Step 1

Preheat the oven to 350 degrees F.

Step 2

Line an 8x8-inch baking dish with parchment paper, leaving a little as an overhang for easy removal later, then generously coat it with nonstick cooking spray.

Step 3

In a large bowl, add the flour, the oats, the brown sugar, the cinnamon, the baking soda, and 1/4 teaspoon of the salt and mix to combine.

Step 4

Add the melted butter, the vanilla extract, and 1/4 teaspoon of the almond extract to the flour mixture and stir until a nice crumble forms and the dough begins to clump together.

Step 5

In the prepared baking dish, add 1 3/4 cups of the crust mixture and evenly press it into the bottom. Place the remaining crust mixture in the refrigerator to reserve for the crumble topping.

Step 6

In a medium pan over medium heat, add the blueberries, the maple syrup, the cornstarch, the remaining almond extract, the lemon zest, and the remaining salt and bring to a boil, while using a wooden spoon to press down and break down the blueberries just slightly.

Step 7

Reduce the heat to medium-low and cook the filling until it has thickened and coats the back of a spoon, about 3-5 minutes.

Step 8

Evenly spread the filling over the crust and sprinkle the reserved crumble mixture over top.

Step 9

Bake the bars until the filling is bubbly and the crumble topping is golden, about 30 minutes.

Step 10

Transfer the baking dish to a wire rack and let the bars cool completely.

Step 11

Transfer the baking dish to the refrigerator and let the bars chill.

Step 12

Use the parchment paper overhang to lift the bars out of the baking dish and cut it into squares.

Step 13

Serve.