Scrub and coarsely chop carrots, turnip, celery, peel and chop onions. Melt butter in 8-quart pan over medium heat. Add chopped vegetables and cook, stirring occasionally, until vegetables turn golden (about 15 minutes). Add water, salt, parsley, bay leaf, and thyme leaves. Cover and bring to a boil. Reduce heat and simmer for 1-1/2 hours. Strain and discard vegetables. Makes 2-1/2 quarts stock. You can adjust the seasoning to suit your taste by adding 2 cloves, peeled garlic, several peppercorns, or your favorite herbs. You can freeze extra stock for future use.