Rinse cauliflower, pat dry. Flip over to remove leaves and stem.
Insert 3-4 cloves of garlic into the crevices of the cauliflower.
Coat outside of cauliflower with olive oil, top with additional minced garlic and salt if desired. Cover with aluminum foil, roast for about 45 minutes.
Check doneness with a knife. There should be little resistance when punctured.
Remove foil, return to oven for additional 10-15 minutes until golden.
Remove from oven, spread butter over cauliflower. Cauliflower will easily pull/fall apart. Lightly season with salt before serving.
Notes
If you are preparing this with a large meal you could roast earlier in the day, set aside, then brown just before serving.