We had this at Grandmother’s house while we were visiting during apple season this past fall. It is AMAZING. Possibly it is actually originally from a Pratt aunt? But I’m giving Grandmother credit here because that is who made it when J ate it.
Preheat oven to 375. Remove stem and all greens from cauliflower. Place in baking dish. In small bowl, combine melted butter, dijon mustard, parmesan cheese, and salt and pepper to taste. Mix well and brush over whole cauliflower. Bake about 1 hour or until tender. Remove from oven and coat with Boursin cheese.