Cook a head cauliflower until fork tender. You can either cook it as a whole head, or in pieces -- whichever you like best. You can use a pressure cooker for about 5 minutes or steam it for about 15 minutes. My family likes it in little pieces because the mayonaise mixture covers it better and it's easier to eat and serve that way.
1/4 cup mayonnaise
2 teaspoons mustard
Mix and then "frost" the cauliflower with the mayo/mustard mixture, then salt and pepper. Top with grated cheddar cheese. Then you can either microwave for about 2 minutes (until cheese is melted) or put it under the broiler in the oven for a little bit of a crust on the cheese. The broiler method is best.