Boil whole cauliflower head in medium pan in lightly salted boiling water. I use enough water to half cover the head. Approximately 10 to 15 minutes. Depends upon the size of the cauliflower. I insert a long tongued fork or sharp knife to test for tenderness. Do not overcook. Drain and set aside for 20 min. to allow cooling so that you may handle it easier.
Preheat Oven 400 degrees. Mix mayonnaise, mustard, and cheeses in a small mixing bowl. Hand mixing is fine.
Put cauliflower in an oven safe baking dish and spread above mixture over entire face of cauliflower. Garnish with paprika and bake until slightly brown. Approximately 20 to 25 minutes for me.