In a large pot, heat olive oil over medium heat. Add chopped onion and sauté until translucent.

Add minced garlic and sliced mushrooms, cooking until mushrooms are tender.

Stir in wild rice, vegetable broth, thyme, salt, and pepper. Bring to a boil, then reduce heat and simmer for 30-35 minutes until rice is tender.

Once the rice is cooked, stir in the heavy cream and chopped spinach.

If desired, mix cornstarch with a little water and add to the soup to thicken. Cook for an additional 5 minutes.

Adjust seasoning with more salt and pepper if needed. Serve hot.