Microwave cauliflower with water for 10-15 mins until VERY soft, drain then mash with potato masher.
Blend in butter and cream cheese.
Add the shredded cheese (reserving about 1/2 cup) and remaining ingredients and stir together.
Put in a casserole dish and top with remaining shredded cheese.
Bake 350 for 20 mins until brown and bubbly.