Dh and I have a certain pasta dish probably once a fortnight, one of the dc says he doesn't like it which then sets the other one off.
Rather than make them something completely different or force them to eat it, I give them this.
Plain cooked pasta, ham or chicken, grated cheese, chopped raw veg so peppers, mushroom, cucumber, salad, tomatoes or whatever else is in the fridge on the side. They seem to enjoy it enough. More than pasta mixed with any kind of sauce.