Combine the wine, port, beef stock, garlic, bay leaves and shallot in a wide saucepan.

Bring to a boil, then reduce the heat to maintain a steady, uncovered simmer. Cook until reduced to 2 cups, about 1 hour or longer depending on the pan and heat. Measure the liquid to check the reduction rather than relying on the clock.

Strain into a heatproof jug, discarding the bay leaves, garlic and shallot. If preparing ahead, cool promptly and refrigerate covered for up to 2 days.

After roasting your beef or lamb, transfer the meat to a board to rest. Pour the pan juices into a heatproof jug or fat separator. Let the fat rise, then skim it off, reserving the meat juices. Leave the browned bits in the roasting pan; discard any burned bits.

If your roasting pan is stovetop-safe, set it over medium heat. Add a little of the wine reduction and scrape up the browned bits. Otherwise, loosen the browned bits with a little hot reduction and transfer the liquid to a saucepan.

Add the remaining wine reduction and reserved meat juices. Simmer until hot, then taste before adding salt and black pepper. If you prefer a smoother sauce, strain again.

Serve hot in a gravy boat. The wine reduction makes about 2 cups before adding the meat juices, enough for 8 servings of about ¼ cup plus drippings.