Step 1

Preheat the oven to 350°F (180°C) and lightly grease a 9-inch tart pan with a removable bottom. Set aside.

Step 2

In a medium bowl, toss together blueberries, sugar, cornstarch, and lemon zests until coated. Set aside.

Step 3

In a separate bowl, combine almond flour, oats, honey or maple syrup, baking powder, and salt. Add softened butter and use your fingers until coarse crumbs form and the mixture holds together when pressed.

Step 4

Remove a heaping 1/2 cup of the crumbs for the topping and pour the remaining crumbs into the prepared tart pan. Press the dough evenly into the pan. Pour the blueberries over the crust, making sure the juices stay behind in the bottom of the bowl.

Step 5

Add the remaining crumble and sprinkle evenly over the top of the berries.

Step 6

Bake for 40-45 minutes or until the filling is bubbling and the crust is lightly brown. At around 20 minutes, tent the tart with foil to prevent it from getting too brown. Let cool completely before slicing into wedges and serving.