Assemble a bunch of vegetables and trimmings. I use carrots, celery,
 bell peppers, garlic, onions. Chop into big chunks. Don't be neat, 
 nobody will see this. Add about 1/2 cup of water to the bottom of the pan.
 Roast in the oven until everything is dark brown. (about 300 - 350 degrees)
 Transfer to top of stove, changing pans if you have to. Cover vegetables
 with water, and use some water to disolve brown solids in roasting pan.
 Cook until the vegetables are really really soft. I usually try and mash
 them a little also. Strain out the vegetables. Continue cooking the stock
 until it is very dark. Vegetable stock is much more delicate than meat stock,
 so it needs more reducing. IMHO. When it looks like a really good French
 onion soup, it’s done. Refrigerate and use as needed.