Heat olive oil in a large soup pot over medium heat. Add onion, garlic, and ground turkey, breaking up the meat as it cooks.
Once the turkey is partially cooked, add carrots, celery, and potatoes. Stir and let cook for a few minutes.
Add lentils, rosemary, thyme, mustard, soy sauce, and chicken broth. Stir to combine.
Turn heat to high and bring to a boil. Cover with a lid, reduce heat, and let simmer for 30 minutes, stirring occasionally.
Season with salt and pepper to taste.
Serve warm, topped with a dollop of plain Greek yogurt or a dairy-free alternative if needed. Enjoy!