In a large mixing bowl, combine GF Oat flour, Almond Flour, oats (not quick oats), ½ teaspoon salt and pecans. Finally, stir in melted butter until moistened and blended.
Toss the sliced apples with cinnamon sugar, coating well. Layering the apples on the crust, however, if you don’t care about pretty layers, then just pour the apples into the crust, delicious either way!
Combine cornstarch, sugar, kosher salt and vanilla in a small saucepan, stir in water, whisking constantly until it boils. Then Pour over the apples and top with reserved crumble topping.