Prepare the Wild Rice: Rinse the wild rice thoroughly and soak it in water for at least 1 hour (or overnight in the refrigerator). Drain well.

Cook the Wild Rice: In a large pot, combine the soaked wild rice with 4 cups of broth. Bring to a boil, then reduce heat and simmer, covered, for 45-60 minutes, or until the rice is tender and the grains have split open. Drain any excess liquid.

Sauté the Vegetables: While the rice is cooking, heat the olive oil in a large pot or Dutch oven over medium heat. Add the onion, celery, and carrots and cook until softened, about 5-7 minutes. Add the garlic and mushrooms and cook until the mushrooms are tender and have released their liquid, about 5-7 minutes more.

Add Herbs and Spices: Stir in the thyme, sage, and nutmeg. Cook for 1 minute, until fragrant.

Make the Roux: In a separate saucepan, melt the butter over medium heat. Whisk in the flour and cook, stirring constantly, for 1-2 minutes, until the roux is smooth and golden.

Thicken the Soup: Gradually whisk the roux into the vegetable mixture in the large pot. Cook, stirring constantly, until the soup begins to thicken, about 2-3 minutes.

Add Broth and Rice: Pour in the remaining 2 cups of broth and bring to a simmer. Add the cooked wild rice and cooked chicken or turkey (if using).

Stir in Cream: Reduce heat to low and stir in the heavy cream (or cashew cream). Heat gently, being careful not to boil. Season with salt and pepper to taste.

Garnish and Serve: Stir in the fresh parsley. Serve hot.