Boil the macaroni in salted water according to package directions then drain in a colander.
While the pasta cooks add a can of coconut milk, 1 can of pumpkin puree, 1/2 cup of water, 1/3 cup of nutritional yeast, 2 tablespoon tapioca starch, 1 tablespoon corn starch, 1 1/2 teaspoon salt, 1/4 teaspoon onion powder, and 1/4 teaspoon garlic powder then give it a stir with a whisk until all of the starch is dissolved.
Turn the stove on to medium heat and stir frequently until your cheese sauce thickens and starts to boil. Then turn down the heat and stir constantly for 1 minute before taking off of the heat.
Add the cooked macaroni to the cheese sauce, stir well and serve hot.
Notes
Use full-fat coconut milk for the creamiest pumpkin cheese sauce.
Add the tapioca and corn starch to cold coconut milk. If you try to add this after you start heating the sauce, it will clump and not dissolve.