Add olive oil to a cast iron skillet or large nonstick pan and heat over medium heat. Add the turkey. Season with salt and pepper. Sauté turkey while breaking apart with a wooden spoon for about ten minutes, until golden. Add the onion, mushrooms, garlic, and thyme. Sauté, stirring occasionally, for another ten minutes.

Pour in the beef stock and add the egg noodles. Stir to combine and to scrape up any brown bits from the bottom of the pan. Add the flour and whisk or stir vigorously to work into the stock. Bring to a simmer. Cover with a lid.

Once the noodles are cooked through, turn the heat off, add in the Greek yogurt, and stir. Remove the sprigs of thyme and then serve.