Microwave the cauliflower in a covered dish for about 4 mintues. Just enough for them to be tender.
Cream together the 6 oz cheddar, 6 oz Monterey Jack, cream cheeses and heavy cream together.
Stir in green onions and bacon.
Drain any liquid from cauliflower and add to cheese mixture. Stir until fully mixed. Add salt and pepper to taste.
Pour into a greased 9 x 13 dish and sprinkle the left over cheeses on the top Cover with foil and bake for 25 mintues. Remove the foil and continue to back until cheese is just turning brown and the casserole is bubbly.
Notes
NOTE; You can substitute other meat for bacon or add several meats together. Ham and bacon make a great combination.