Rich Pork Stock

1. Place reserved pork bones in a 10x15" pan with onions and carrots. Roast in a 450F. oven, mixing occasionally, until bones are well browned, 40-50 minutes. 2. Add 1/2 cup water to pan; stir vigorously to free browned bits. Scrape mixture into a 5-6 quart pan. Add 1 quart water, celery, and thyme. Bring to a boil over high heat, then cover and simmer for 1 1/2 hours. 3. Uncover pan and boil over high heat until liquid is reduced to 2 1/2 cups, about 10 minutes. Pour mixture through a fine strainer into a bowl. Discard bones and vegetables. If stock is made ahead, cool, cover, and chill up to 2 days. Skim or lift off fat and discard.