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 Pepper Jack, cream cheeses and heavy cream.
Stir in green onions, garlic, 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 leftover cheeses on top. Cover with foil and bake for 25 minutes. Remove the foil and continue to bake until the 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.