Bring a large pot of water to a boil. Add cauliflower florets and cook 5-6 minutes. Drain. Run cold water over cauliflower and drain again. (Or drench in an ice water bath. Drain well.)
Place well-drained cauliflower in a small casserole dish (glass pie pan or quiche dish works well too).
Melt 2 tablespoons ghee in a medium saucepan. Add cashew milk, pepper, nutmeg and salt. Whisk and bring to a boil. Add cheese(s) if using and continue whisking until thickened to coat the back of a spoon. This should take a few minutes. Don’t let it get too thick and gloppy. If it’s too thick, add some water or more cashew milk to thin out.
Pour sauce over cauliflower and give a little stir to make sure it’s all coated.
Pulse toasted grain free bread in a mini food processor or just break it up with a fork in a small bowl. Sprinkle crumbs on top of cauliflower and drizzle with 1 tablespoon of melted ghee.