Bring a large pot of salted water to a boil over medium heat.
Place the drained roasted red peppers, soy milk, olive oil, salt, garlic, tahini, red pepper flakes and nutritional yeastin a blender and puree until creamy. Season to taste as needed with salt/pepper and add to a large skillet. Simmer over medium heat while you make the pasta.
Place the pasta in the water and cook until under al-dente, about 1-2 minutes before the recommended time on the package. The pasta should be still pretty toothy, but not hard.
Drain the pasta and reserve 1 cup pasta water. Add the pasta to the sauce on the stove and cook, adding a splash of pasta water at a time to loosen the sauce as needed as you toss the sauce with the pasta to finish cooking.