This buttery, caramelized crown of cauliflower proves you don’t need to get complicated to achieve dramatic, decadent results in the kitchen. Whole-roasting provides an even surface for basting with brown butter, which trickles into the crevices and crisps the exterior. Finish simply with a shower of salt, and you've got a beautiful side dish hearty enough to serve as a main.
Preheat oven to 450 degrees F (425 degrees F, if using convection). Cut the stem off the cauliflower as close to the florets as possible to provide a flat base for roasting. Remove and discard any green leaves. Place the cauliflower in a cast-iron skillet and rub oil all over the surface. Place in the oven and roast, 30 minutes.
Remove from the oven; the cauliflower should be light brown and slightly softened. Use your hands to carefully mash the softened butter onto the top of the cauliflower. Place back into the oven for 10 minutes.
Remove from the oven. Tilt the skillet to pool the brown butter at one end, then use a spoon to thoroughly baste the cauliflower. Test for doneness by inserting a sharp knife into the center: the cauliflower should be completely tender with no resistance. If it needs a bit more time in the oven, baste one final time and place back in the oven for 10 more minutes.
Remove from the oven, baste again, and test for doneness. Sprinkle with a generous pinch of salt and serve whole or cut into wedges.