Preheat the oven to 350°F.

Place strawberries in a medium saucepan over medium heat. Bring to a boil, stirring every few minutes.

Once the strawberries start to bubble, mix in the lemon juice and maple syrup.

Using a potato masher, mash the berries, leaving some in small pieces.

Cover and let simmer for 10 minutes.

Add the tapioca flour to the strawberries, and simmer for another 5 minutes until thick.

In a large bowl, combine all the crust ingredients. Mix until well incorporated and a dough forms.

In a parchment paper-lined 8 x 8 or 9 x 5 baking dish, add ⅔ of the oat mixture, pressing down the dough to create a crust. Reserve the rest for the crumble.

Bake the crust for 10 minutes.

Remove crust from oven and spread the filling strawberry filling on top of the crust.

Crumble on the rest of the oat mixture on top of the strawberry filling.

Bake for an additional 20-25 minutes, until the crumble is golden.

Let cool for 10 minutes before slicing into bars.