This Wild Rice and Spinach Gratin is a delicious and nutritious side dish that combines the earthy flavors of wild rice with the freshness of spinach. The rice is cooked until tender and then mixed with sautéed onions, garlic, and spinach. A creamy sauce made with milk, cheese, and spices is poured over the rice and spinach mixture, and then the dish is baked until golden and bubbly. The result is a comforting and satisfying gratin that pairs well with roasted meats or can be enjoyed on its own as a vegetarian main course.