Chop off the florets from 1 large head cauliflower and place them in a steamer basket set in a pot filled with 1 inch boiling water. Cover and steam until soft, about 20 minutes. Puree the cauliflower with 3 tablespoons butter, a pinch of nutmeg, and salt to taste. Fry sage leaves in a few tablespoons butter; pour over the mash.
Use a food processor or immersion blender to puree these veggies-they're too fibrous for a potato masher.