Preheat the oven to 350 degrees F. Line a 9×9 inch pan with parchment paper and spray the pan with nonstick cooking spray to prevent sticking. I sprayed generously with avocado oil spray and skipped the parchment paper.
To make the base + topping: In a large bowl, use a fork to mix together the almond flour, oat flour, oats and salt. Add in melted butter, pure maple syrup and vanilla extract and stir until a nice crumble forms and dough begins to clump together. Reserve 1 cup of the mixture for the topping and set aside. Use your hands to evenly press the remaining dough into the bottom of the pan. Bake the crust for 10 minutes, remove and cool down until you prepare the filling.
Make your strawberry filling: place a medium pot over medium heat. Add in strawberries, maple syrup, arrowroot starch, lemon juice and almond extract. Bring to a simmer, then reduce heat to low and cook for 3-5 more minutes, stirring frequently until the mixture is slightly thickened and strawberries release some of their juices.
Pour strawberry filling over the crust and use a spoon to spread over the top. Top with the reserved topping. Bake for 45 minutes or until filling bubbles along the edges and top is golden brown. Allow to cool completely before cutting into, otherwise they will fall apart.