In a large pot, heat oil over medium-high heat. Add onion, celery, and carrot. Sprinkle with salt and pepper. Cook, stirring frequently, until onions are translucent (about 5 minutes). Add turkey, parsley, sage, thyme, chicken stock, and water. Raise heat to high and bring to a boil.
Once boiling, add quinoa and stir. Reduce heat to medium and continue to simmer rapidly until quinoa is cooked – 15 to 20 minutes, stirring occasionally. You should see “tails” appear on the quinoa.
Remove from heat and slowly add milk while stirring soup. Return to low heat to reheat if needed. If desired, use more milk or water to achieve a thinner soup. We love it thick!