Brown: Brown the mushrooms in the oil and butter, then cook the onion, carrots, and celery 5 to 6 minutes. Add garlic and herbs for 30 seconds.
Thicken: Stir in the flour for 1 minute, then slowly add the broth while scraping the pot.
Simmer: Add the wild rice, bay leaf, salt, and pepper. Cover and simmer 40 to 45 minutes, until the rice splits.
Add turkey: Stir in the turkey and spinach for the last 5 minutes. Remove the bay leaf.
Finish: Take the pot off the heat, temper the yogurt with two ladles of hot broth, and stir it in. Add lemon juice, salt to taste, and parsley.