Because a cast-iron Dutch oven holds an even temperature, preparing steak in one delivers an evenly cooked, tender, juicy piece of meat. Although you must properly season a Dutch oven before you use it the first time, additional seasonings may be needed from time to time. This is especially true if you're planning to cook something that tends to stick. Because it does not have any plastic or other parts that can melt, cast iron moves easily from the stove top to the oven.
Preheat your oven to 400 degrees.
Season the Dutch oven. Coat the inside of the Dutch oven with a light film of lard. If you prefer, use shortening or vegetable oil. Place the Dutch oven upside down in the hot oven on a piece of aluminum foil. Heat for 30 minutes. Remove the cast-iron oven, and let it cool.
Rub olive oil over 4 filet-mignon steaks, about 4 oz. each, and coat with 2 cloves minced garlic, pressing garlic into the meat. Set aside.
Bring 1 1/2 cup wine and 3 tbsp. unflavored balsamic vinegar to a boil in a small saucepan on the stove over medium heat. Wrap 4 whole cloves, 1 tsp. crushed peppercorns and 1 bay leaf in a piece of cheesecloth, and add to wine-vinegar mixture. Boil for about 15 minutes. Remove cheesecloth bundle. Turn heat to low and keep warm.
Place Dutch oven on high heat on the stove. Place steaks in the Dutch oven. Cook on each side for 1 to 2 minutes, turning with tongs.
Put Dutch oven in hot oven, and continue to cook to desired doneness, about 3 to 5 minutes.
Test for doneness with a meat thermometer. Let meat rest for 5 to 10 minutes, and add any juices that seep out to the wine mixture.
Pour wine mixture over steaks before serving, and season with salt and pepper to taste.
Properly seasoning your cast iron gives it a waterproof, glossy finish similar to a nonstick pan. Always use potholders, as cast iron can get extremely hot and is an efficient heat conductor. Steaks are rare when the internal temperature reaches 120 degrees. For medium rare, allow the steaks to cook to 125 degrees, and for well-done, allow internal temperature to reach 130 degrees. Steaks continue to cook after they're removed from heat, so remove from heat just before they reach optimal temperature, based on your preferred level of doneness.
Do not salt steak before cooking. Salting causes the meat to release moisture.