Put the chicken into a saucepan or casserole with the onions and carrots ... Meanwhile cook the cauliflower florets in boiling salted water until al dente. Drain and refresh under cold water ...

Remove your roasted cauliflower and butternut from the oven; they must be fork-tender. Roughly chop them and add them to the pasta. Mix well, then place them in a gratin or casserole dish.