Preheat the oven to 350 degrees F.

Cut out stem and core from cauliflower, cut into pieces. Rinse well.

Put a couple of inches of water in a large pot and bring to a boil. Add the cauliflower and cook until tender but not too soft, about 8 minutes.

Drain well and mash with a potato masher, leaving a few chunks.

Mix in the sour cream, heavy cream, green onions, egg, cheese and bacon.

Spread evenly in a medium sized buttered casserole dish. Sprinkle a handful of additional shredded cheddar cheese over the top.

Bake for 30 minutes or until cheese is melted.