Preheat the oven to 400°F.

Bring a large pot of water to a boil. Season with 1⁄2 teaspoon of salt. Carefully drop the cauliflower into the boiling water and cook for 5 minutes.

Drain thoroughly, and place the florets on paper towels to soak up any remaining moisture. Put the cauliflower in a large bowl and set aside.

To a large skillet over medium heat, add the heavy cream and bring to a simmer. Whisk in the cream cheese until smooth. Add the Cheddar cheese, mozzarella cheese, and garlic. Whisk until the cheeses melt, about 2 minutes.

Remove the cheese sauce from heat and pour over the cauliflower. Stir to coat the florets evenly. Sprinkle with the remaining 1⁄2 teaspoon of salt and the pepper.