Rigatoni a la huancaina is a cheap Peruvian-inspired meal that can be served as a main or as a side dish. Huancaina is a Peruvian sauce made with aji amarillo (yellow chilli) that is traditionally served with boiled potatoes.
Heat ghee or oil in a pan to medium-low heat. Add onion and cook until soft (10-15 minutes), stirring often.
Add garlic and aji amarillo paste, cook for another 5 minutes.
Cook pasta according to package instructions.
Place onion mixture in a food processor or blender with cheese and milk. Blend to desired consistency (I like mine a little chunky) and season to taste.
Drain pasta, toss with sauce and serve with chopped parsley, Parmesan, optional protein and salad.