Begin by removing all the stems from a head of cauliflower. Place the cauliflower florets in an 11x7 baking dish lightly greased with olive oil. Roast the cauliflower for 15 minutes at 400 degrees F.
While the cauliflower is roasting, prepare the cheese sauce. In a small pan combine the butter, garlic, milk, heavy cream, and cream cheese over medium heat. Whisk until the mixture is smooth.
Stir in 1 cup of the cheddar until completely melted. Bring the mixture to a slight simmer until it has thickened.
Pour the cheese sauce over the roasted cauliflower, top with the remaining shredded cheese. Bake 20-25 minutes.