In a large pot, melt butter, and saute onions until translucentAdd chicken stock, bring the stock to a boil, and reduce to a simmer.Add potatoes, chopped celery, carrots, and thyme.When the potatoes, celery, and carrots are tender to your liking, about 2-30 minutes.Optional step: Combine cornstarch with 1/2 C water, and mix thoroughly until starch is completely dissolved and a slurry is formed. Bring broth to a boil, and add cornstarch slurry to the broth while stirring constantly for 3 minutes to cook the cornstarch and thicken the broth.Now, turn off the heat and add the chicken and noodles. Stir to mix the soup. Season with salt and pepper and/or more chicken base to taste.Serve immediately with toasted French bread or crackers, or keep warm on the stove in the pot so people can help themselves. An enamel-coated cast iron pot works well for this. Without the stove flame or heat source, it will hold heat for a long time.