This spinach and mushroom casserole is a healthy and flavorful dish that is perfect for vegetarians and meat-lovers alike. Fresh spinach and mushrooms are sautéed with garlic and onions until tender and then combined with a creamy sauce made from milk, cheese, and a touch of nutmeg. The casserole is then baked until golden and bubbly, creating a deliciously cheesy and comforting dish. The combination of spinach and mushrooms provides a good dose of vitamins and minerals, while the creamy sauce adds richness and depth of flavor. Serve this spinach and mushroom casserole as a side dish or a main course for a satisfying and nutritious meal.