Homemade Beef Stock for French Onion Soup

Preheat oven to 400 degrees. Arrange beef bones and oxtail in a single layer in a heavy roasting pan (not glass). Coat with oil. Roast, turning once, until deep brown, about 45 minutes.

Add tomato paste, onions, leeks, celery, carrots, and garlic, stirring well. Roast until vegetables are browned and tender, about 40 minutes.

Meanwhile, make a bouquet garni by wrapping parsley, thyme, bay leaves, and peppercorns in a square of cheesecloth. Tie bundle with kitchen twine; set aside.

Transfer bones and vegetables to a large stockpot; set aside. Pour off fat from roasting pan. Set pan on stove across two burners. Add wine, and bring to a boil, deglazing pan by scraping up any brown bits from bottom with a wooden spoon; boil until wine is reduced by half, about 3 minutes. Add to stockpot.

Add 6 quarts (24 cups) water to stockpot. Bring to a boil. Reduce heat; bring to a gentle simmer. Add bouquet garni. Simmer, uncovered, over low heat, 3 hours.

Carefully pass stock through a fine sieve into a large bowl or pot; discard solids. Let stock cool completely.

Transfer stock to airtight containers. Refrigerate at least 8 hours or up to 3 days before using (fat will solidify; discard it before using). The stock can be frozen up to 4 months.