Cook pasta noodles according to the package- you'll need ½ pound of pasta. Save at least ½ cup of salted pasta water to thin out the sauce.
Dice the onion and garlic. Sauté the onion on medium-high heat until soft and starting to brown, about 5-7 minutes. Add in the garlic and cook for another 2 minutes.
Toss the onion and garlic into a blender along with the roasted red peppers- make sure you drain the liquid off the peppers, no need to rinse them. Add in the nutritional yeast, tomato sauce, dried oregano, dried basil, salt, pepper, and red pepper flakes as well. Blend until smooth.
Taste and adjust the following: salt, pepper, and red pepper flakes.
Pour the blended sauce into a pan on medium heat and stir until hot- add in a splash of the pasta water to thin out the sauce if desired. You may or may not need the entire ½ cup.
Toss in the cooked pasta and stir to coat. Top with fresh parsley or basil and serve.