PREP: Position a rack in the center of the oven and preheat the oven to 425ºF. Bring a large pot of water to boil. Add a palmful of salt when boiling. Drop the florets and cook for 7-8 minutes, or until firm but tender. Drain and set aside.

MIX: Place the heavy cream in a 1 cup measuring cup and stir in pressed garlic, a big pinch of salt, a few shakes of white pepper, thyme leaves, mustard powder, and ground nutmeg. Spray a medium (such as 12x8) baking dish with cooking spray. Add half of the cauliflower to the dish. Dot with half of the butter and sprinkle half the cheese on top. Add the remaining cauliflower on top and dot with remaining butter and cheddar cheese. Pour the heavy cream mixture on top.

BAKE: the mixture uncovered for 30 minutes or until bubbly and golden. If at any point the casserole starts browning too much, cover loosely with a piece of foil. You can pop it under the broiler if you want it more golden on top for the last 30 seconds or so! Serve warm!