1. Set your oven's broiler function on to high heat.
2. Melt the butter in a 12-inch cast-iron skillet. Add the spinach, artichokes, and onion and sauté, stirring frequently, for five minutes until spinach is wilted and onions are translucent. Add the garlic, salt, black pepper, cayenne pepper (optional), sage, and nutmeg and sauté for an additional minute