Bring a large pot to a boil and add the wild rice. Reduce heat to simmer and cook uncovered until tender, about 45 minutes. Drain any excess water and set aside.
While the rice cooks, heat olive oil in the same pot over medium heat. Add the chopped onion, diced carrots, and celery, cooking until they soften and become fragrant, about 5-7 minutes. Stir occasionally to prevent sticking.
Add the minced garlic to the vegetables and cook for another minute until it releases its aroma. The mixture should sound slightly sizzling and smell rich and warm.
Pour in the vegetable broth and stir to scrape up any browned bits from the bottom of the pot. Bring the mixture to a gentle simmer, allowing the flavors to meld for about 10 minutes.
Stir the cooked wild rice into the broth and vegetables. Let the soup simmer gently for another 10 minutes to allow the flavors to integrate and the rice to reacquire some heat.
Pour in the heavy cream if using, and stir well to create a rich, creamy texture. Season the soup with dried thyme, salt, and pepper to taste. Let it cook for another 2-3 minutes, allowing the flavors to balance.
Turn off the heat and give the soup a final stir. Check the seasoning and adjust salt and pepper as needed. The soup should be fragrant, with a slight thickening from the cream, and have a hearty, textured consistency.
Ladle the hot soup into bowls and serve immediately, garnished with fresh herbs or a drizzle of cream if desired. Enjoy the comforting and wholesome flavors of this seasonal dish.
