Boil the cauliflower 5 min, put in pan. Make a cheese sauce, spread over top. Sprinkle cheese on top of everything. Bake 15-20 minutes until bubbly.
Boil water. Oven to 400F. Cut cauli into florets. Boil cauli 5 min, drain, arrange in bottom of pan. While it’s boiling, grate cheese. Reuse pan for sauce. Make a cheese sauce. Heat butter, flour; fry. Add milk and mustard to pan. Bring to boil. Simmer 2 min while whisking. Turn off heat. Whisk in cheese. Pour the cheese sauce over the cauliflower. Sprinkle cheese on top.
There is a video from the series “things to do with fall and winter vegetables”