Boil the makaroni until almost aldente, add salt and pepper

Chop the onion and sautee the onion with butter until it smells good

Turn down the heat add macaroni and other ingridients including a bit of water from boiling macaroni

Cook until the ketchup already mixed with the macaroni and the macaroni a little bit dry and red

Add a little bit salt and pepper if it's not enough taste