In a large bowl, toss the cauliflower florets with butter. Season with sea salt and black pepper.
Transfer the cauliflower to a small casserole dish in a single layer. Roast in the oven for 15-20 minutes, until crisp-tender.
Meanwhile, in the same bowl, whisk together the sour cream and heavy cream, until smooth. Stir in the minced garlic and half of the cheddar cheese.Season sauce with sea salt and black pepper.
Add the cauliflower to the bowl and mix with the sauce.
Return the cauliflower mixture to the casserole dish. Top with remaining cheese.
Bake for 5-10 minutes, until the cheese melts. Enjoy!