MAKES 2 QUARTS/2 L
For a quicker, paler beef stock, skip the roasting and simply add the bones and vegetables to the pot, cover with cold water, bring to a boil, skim off the foam, and gently boil for 2 hours. (In Spain, they call this fondo blanco, literally “white background,” but meaning a paler as opposed to a darker stock.) For a bolder, stand-alone stock that can be used as a soup broth, add % cup/60 ml red wine once the vegetables have browned, stirring for 2 minutes to let the alcohol burn off and scraping to get anything stuck from the bottom of the pan before continuing with the recipe.
Preheat the broiler. Lightly season the bones with salt. On a baking sheet or in a roasting pan, arrange the bones and slide into the oven. Broil until browned, turning as needed, 10 to 15 minutes.
Meanwhile, in a large stockpot, heat the olive oil over medium heat and add the leeks, carrots, celery, and garlic. Cook until browned, about 10 minutes. Add the turnips, peppercorns, and browned bones and their juices from the pan; season with salt; and cover with 3 quarts/3 L cold water. Bring to a boil, reduce the heat to medium-low, partly cover the pot, and gently boil for 2 hours, skimming off the fat that floats to the surface.
Remove the pot from the heat and let cool. Strain the broth through a conical strainer. Gently press out the remaining liquid from the vegetables, and discard the solids.
Store in the refrigerator for up to 3 days or freeze for up to 3 months.