Mix all the filling ingredients together until well combined. Pour into 9-inch baking dish.
Mix together crumble ingredients in a small bowl. Dot the topping over the filling.
Bake for 25-35 minutes until the center is just set.
Allow the casserole to cool, serve slightly warm or chilled.
Sweet Potato Puree- The recipe, as written, used one 15 oz can of organic sweet potato puree. If using fresh sweet potatoes, you may need to add up to a half cup of almond milk. Bake times vary based on the type of sweet potato chosen and the water content. Coconut Sugar- The sugar in the filling is very flexible. You can use honey, maple syrup, brown sugar, or regular sugar. Coconut Oil- I like coconut oil for its mild flavor and healthy fats. You can use vegetable oil, butter, or dairy-free butter. But coconut oil does give the best results, in my opinion.Gluten-Free Flour Blend- You can use any gluten-free flour brand, it doesn't need to contain xanthan gum but it is fine if it does. Any all-purpose flour or oat flour will work equally well.