In a large non-stick skillet, cook the potatoes, carrot and onion in olive oil and 1 cup water. Cover and cook over medium heat, stirring occasionally.
Do not let the vegetables dry out; if they are cooked but water remains in the skillet, remove the lid to allow the excess water to cook off. Once they are fork tender, transfer to a blender or food processor and pulse until smooth.
Add nut or seed butter, salt, garlic, oil, mustard and dried mustard, lemon juice, nutritional yeast pepper and water. Pulse until fully integrated. Taste and add more of any particular ingredient to adjust taste to your preference. Thin with more hot water, if necessary.
Prepare noodles according to package directions. Drain. Add sauce, stirring to evenly coat noodles. If desired, sprinkled crushed corn chips on top and bake for 10 minutes at 400° F to crisp the top.
Serve warm, tossed with gluten-free macaroni noodles or use as a nacho cheese dip or spread!
To drizzle over chips, thin the sauce with hot water until it is the consistency you desire.
(Approximate nutrition for each serving: 192 calories, 15g total fat, 2g saturated fat, 0g trans fat, 0mg cholesterol, 307mg sodium, 14g carbohydrate, 2g fiber, 2g sugars, 3g protein, 5Est GL.)