1.  Preheat oven to 350 degrees.  Chop cauliflower into small florets.  Place in a large, microwave safe bowl and add 3/4 C water.  Cover with plastic wrap and microwave on high for 5 minutes.  Stir the cauliflower, cover, and heat again for about 5 minutes until the cauliflower is tender, but not mushy.
2.  While cauliflower cooks, mix together all the remaining ingredients, leaving enough of both shredded cheeses to sprinkle over the top of the finished dish.  Once the cauliflower is finished cooking, drain away the water and add the hot cauliflower to the cheese mixture.  Stir it all together well.
3.  Pour into a greased 2 quart casserole dish and sprinkle on the remaining cheeses.  Cover with aluminum foil and bake for 25 minutes.  Remove the foil and continue to bake until the cheese is browned and bubbly, about 15 minutes more.