
Preheat oven to 350 degrees and lightly grease a 13x9in. baking dish.
Boil cauliflower florets in salted boiling water for about 3 minutes.
Drain all water from the cauliflower and dump into prepared dish.
Melt butter in a large skillet over medium heat and cook garlic until fragrant (1 minute).
Add flour and stir for 2 minutes.
Add milk 1/2 cup at a time and bring to a simmer.
Add cream cheese and whisk to combine.
Remove from heat and add 1 cup of the sharp cheddar; stir until melted.
Season with salt and pepper.
Pour cheese sauce over cauliflower and stir to evenly coat.
Set aside 1 tablespoon each of cooked bacon and green onions, then stir the rest into the cauliflower.
Top with remaining cheese, bacon and green onions.
Bake for about 30 minutes, or until cheese is melted completely.