"World's Greatest Vegetable Broth" (It's Pretty Good...)

8 ounces celery root, scrubbed or peeled and cut into 1-inch pieces
1 pound sweet onions, coarsely chopped
8 ounces carrots, cut into 1-inch pieces
8 ounces tomatoes, cored, halved
8 ounces green bell pepper, cut into 1-inch pieces
1 head garlic
1 tablespoon olive oil
6 whole cloves
1 bay leaf
12 whole black peppercorns
Whole coriander seeds, green cardamom pods, star anise, cinnamon stick, roasted cumin seeds as desired
2 quarts water
 
Heat oven to 450 degrees F.
 
Toss celery root, onion, carrots, tomatoes, and bell peppers with olive oil.  Place vegetables in a roasting pan.  Slice top off the head of garlic and pour a little olive oil over the exposed cloves.  Add garlic to roasting pan, and place pan in oven.  Stir the vegetables every 15 minutes.  Cook until all of the vegetables have browned and the onions start to caramelize, 30 to 45 minutes.
 
Put the browned vegetables, some or all of the roasted garlic cloves, cloves, bay leaf, peppercorns, other spices as desired, and water, into a large stock pot.  Bring to a full boil.  Reduce heat to simmer.  Cook uncovered until liquid is reduced by half.
 
Pour the broth through a strainer, catching the broth in a large bowl or pot.
 
Makes 1 quart.  Can be frozen for later use.
 
From AllRecipes, with changes