2 heaping tbsp. mayonnaise
1 tsp. mustard
1/4 c. chopped onion
1 head cauliflower
2 tbsp. water
1 c. Monterey Jack cheese, grated
1 c. Cheddar cheese, grated

Trim heat; put head and water in microwave for 6 minutes on HIGH. Turn 180 degrees for six minutes more.

Mix mayonnaise, mustard, onion and pour on head. Sprinkle cheeses on sauce. Cover and cook on MEDIUM HIGH for 2 minutes until cheese melts.