Cook macaroni pasta according to package directions until al dente. Drain and set aside.
In a large saucepan, melt vegan butter over medium heat.
Whisk in gluten-free flour and cook for 1-2 minutes to create a roux.
Gradually add non-dairy milk, whisking continuously to prevent lumps.
Simmer sauce for 3-5 minutes until thickened.
Stir in nutritional yeast until well combined.
Add optional vegan cheddar cheese if using and stir until melted.
Season with salt and pepper to taste.
Add cooked pasta to the cheese sauce and toss until well coated.
Serve immediately while hot.