This recipe has been adapted from Dr. Andrew Weil's book, "The Healthy Kitchen" (Knopf, 2005) and is used in Andy's Roasted Winter Squash and Apple Soup.
Heat olive oil over medium heat in a large pot. Add vegetables, and saute until lightly browned. Stir in parsley, marjoram, thyme, bay leaves, and cold water. Bring pot to a boil, reduce heat, cover, and simmer for 1 hour.
Strain stock through a fine sieve or a cheesecloth-lined colander. Press or squeeze vegetables to extract all liquid; discard vegetables.
Use immediately, or freeze for later use.