NOTE: This is a very low fat version of those macaroni and nutritional yeast "cheese" recipes that traditionally have way too much fat. I had it for the first time last week, and it was really good. When I made it, I used chopped tomatoes and roasted red pepper as the optional ingredients.
Cook the pasta in a large pot of salted water until just tender. While the pasta is cooking, preheat the oven to 350° F and make the sauce.
Cook the potato, carrot, and onion in the water in a small covered saucepan. When the carrot is tender, add the cooked vegetables to a blender along with the other sauce ingredients. Blend until very smooth.
Drain the cooked macaroni and mix it with the sauce and optional vegetables in a casserole. If desired, top the casserole with seasoned bread crumbs.
Bake for 20 minutes.
Servings: 2 - 4