There are several recipes for veggie stock in my archives, but I most often go back to a simple stock recipe that was found in an old diabetic cookbook which I've punched up a bit with the addition of fire roasted tomatoes, a small piece of chipotle or other dried chile, and a few other ingredients. It's so simple to make - as are pretty much all vegetable stocks - that I make it often.
I use it as a basis for vegetable soups of all sorts, use it as the liquid in which to cook rice and other grains, and sometimes just heat up a big cup and enjoy sipping it on a cold day.
Here's a recipe that I've used a number of times:
Cooking of the Italian Jews
This particular stock recipe comes from the old Jewish settlement in the town of Pitigliano, in Tuscany, and is well over 150 years old.
2 medium leeks (white part)
2 quarts cold water
2 large carrots, peeled and diced
2 medium turnips, peeled and sliced
1 medium onion, sliced
2 large stalks of celery cut into 2-inch pieces
3 - 4 sprigs Italian parsley
2 medium parsnips, peeled and cut up
2 medium sweet potatoes, peeled and quartered
2 large Turkish bay leaves (Do not use Bay Laurel leaves)
2 large fresh basil leaves or 1 tsp dried basil
1/2 tsp whole black peppercorns
2 green zucchini, trimmed and cut up
1/4 lb green beans, trimmed and cut up
1 Tbs salt (optional, but no more than this amount)
Remove roots and trim tough tops from leeks. Quarter leeks lengthwise and cut into pieces about 2 - 3 inches long. Clean leeks thoroughly with plenty of cold water. Put leeks, and all the other ingredients, into a large stockpot with 2 quarts of cold water.
Bring to a boil, reduce heat, and simmer, covered, for about 30 - 45 minutes. Strain through a fine strainer or a couple of layers of damp cheesecloth.