Yes, this is a weekend project, but it has a big flavor payoff. (Or buy some at a gourmet store, or order from bonewerksculinarte.com.) To store, spoon 1-tablespoon portions of cooled Glace into an ice-cube tray. Cover with plastic wrap; freeze. Place cubes in a container; freeze up to three months.
3 pounds bone-in chicken thighs, skinned
3 quarts cold water, divided
4 cups coarsely chopped yellow onion
2 cups coarsely chopped celery
1 cup coarsely chopped carrot
12 black peppercorns
10 parsley sprigs
3 thyme sprigs
2 bay leaves
How to Make It
Preheat oven to 425°.
Place chicken in a broiler pan or shallow roasting pan coated with cooking spray. Bake at 425° for 1 hour, turning thighs after 30 minutes.
Place chicken in a large stockpot. Carefully add 2 cups cold water to broiler pan, scraping to loosen browned bits; pour liquid into stockpot. Add onion and remaining ingredients. Add remaining 10 cups cold water; bring to a boil. Reduce heat, and simmer 2 hours; skim surface occasionally, discarding foam.
Strain stock through a fine sieve lined with cheesecloth or a thin cotton dish towel into a large bowl; discard solids. Cool stock to room temperature. Cover and chill stock for 8 hours or overnight.
Skim solidified fat from surface of stock, and discard. Place stock in a medium saucepan; bring to a boil. Reduce heat, and simmer until syrupy and reduced to 6 tablespoons (about 1 hour and 15 minutes), skimming foam as needed.