Preheat the oven to 400 degrees. Spray 4 individual gratin dishes with cooking spray.
Heat the oil in a large skillet over medium-high heat. Add the mushrooms and sauté until they begin to brown, about 3 minutes. Add the ham and continue to cook, stirring, until the ham is lightly browned, about 2 minutes. Add the garlic and the spinach, 1/4 teaspoon salt and nutmeg, and sauté until the spinach is wilted and liquid has evaporated.
Place the gratin dishes on a baking sheet. Divide the mushroom and spinach mixture among the gratins. Top each with 2 eggs and season with remaining salt and black pepper to taste. Drizzle each with a tablespoon of cream and sprinkle the top with Parmesan. Place in the oven and bake for 12 to 14 minutes, or until the whites of the eggs are set and the yolks are still runny. (Rotate the baking sheet once if they aren't cooking evenly.) Serve hot with toasted bread.
Nutrition information per serving:
Calories490Fat24 gSodium1,270 mg