This classic stock doubles as a cold-weather tonic when rewarmed on its own -- it's also an essential building block to any chicken soup worth your grandmother's recipe.
Place chicken, vegetables, bay leaves, and peppercorns in a large stockpot with 3 quarts water. Bring to a boil, skimming impurities as they rise to the top. Reduce heat and simmer, skimming occasionally, until richly flavored, 3 to 4 hours. Strain through a fine-mesh sieve into a heatproof container. Refrigerate at least 8 hours to allow fat (schmaltz) to solidify on top; skim and reserve. Store in refrigerator up to 3 days, or freeze up to 3 months.