Cook the bacon in a skillet until crisp; set aside on a paper towel then crumble.
Fill a large pot with water, bring to a boil and add cauliflower and garlic. Boil until the cauliflower is soft, about 15-20 minutes. Drain, and return to the pot.
Preheat the oven to 350°F.
Add the buttermilk, butter, salt and pepper to the cauliflower and purée with a hand blender. If you don’t own a hand blender, a regular blender would work fine as well.
Mix in 1 tbsp of the chives and transfer to 4 individual casseroles (3/4 cups each) or one 8 x 8 casserole dish and top with cheddar and crumbled bacon.
Bake in the oven until the cheese melts, about 5 minutes then top with remaining chives.
