Cook the fettuccine according to package instructions in a large pot of salted boiling water. Drain and set aside, reserving 1/2 cup of the pasta water.
In a blender, combine the roasted red bell pepper, almond milk, nutritional yeast, olive oil, minced garlic, onion powder, garlic powder, salt, and pepper. Blend until smooth and creamy.
In a large skillet over medium heat, pour the blended sauce and cook for about 5 minutes, stirring occasionally. If the sauce is too thick, add reserved pasta water a little at a time until desired consistency is reached.
Add the cooked pasta to the skillet and toss until well coated with the sauce. Heat for an additional 2-3 minutes, allowing the pasta to absorb some of the sauce.
Serve hot, garnished with fresh basil or parsley if desired.