Cook the gluten free pasta according to package directions. Once it's done, drain it and set it aside.
While the pasta cookies, in a medium saucepan melt the buttery spread, and saute the onion until soft, about five minutes. Stir in the gluten free flour and cook for about 2 minutes to remove the raw flour taste.
Slowly add in the dairy free milk.
Cook over medium heat, stirring constantly until mixture almost boils; reduce heat to a simmer, but keep stirring constantly.
Gradually stir in the dairy free cheese. Add the salt, pepper, and garlic powder. Stir until the cheese melts.
Add the tuna and stir, then add the pasta and stir to combine.
Top with bread crumbs if desired. You could also top this with crushed gluten free crackers or potato chips.
Notes
Store leftovers in an airtight container in the fridge. They should stay fresh for about 3 days.