For the fruit base, toss all ingredients, from the chopped rhubarb to the All-Purpose Flour Mix in a medium bowl.
Pour the mixture into a 3 qt. soufflé dish or 8x11 baking dish.
For the crisp topping, combine all ingredients, from the Muffin Mix to the vegan shortening, in the bowl of a food processor and pulse until combined into a streusel like topping. Sprinkle over the fruit layer.
Bake for 20 minutes or until the topping is golden brown and the fruit is bubbling. Cool 30 minutes before serving.