1 medium cauliflower
1/2 c. mayonnaise
1 tsp. finely chopped onion
1 tsp. prepared mustard
1/2 c. shredded cheese

Wash cauliflower and remove some of the core. Wrap in wax paper and place on serving plate. Cook 10 minutes on high; let stand a couple minutes before removing wax paper.

Combine other ingredients, except cheese. Spread on cauliflower; cook 1 - 1 1/2 minutes. Sprinkle with cheese and let stand to melt the cheese.