Start by drying your lamb neck fillets very well. Season them heavily with salt and black pepper. Rub the spices into the meat with your hands. This ensures a flavorful crust during the first sear.

Heat olive oil in your heavy skillet over high. Place the lamb in the hot pan carefully. Sear every side until it is dark brown. Remove the meat and set it on a plate.

Lower the heat and add the diced vegetables. Cook the carrots, celery, and onions until soft. Add the smashed garlic cloves to the warm pan. Stir them until they smell very fragrant and sweet.

Pour the red wine into the hot skillet now. Use your spoon to scrape the brown bits. These bits hold all the intense meaty flavor. Let the wine bubble and reduce by half.

Place the lamb back into the Dutch oven. Pour the wine and the beef stock over. Add the fresh rosemary sprigs to the liquid. The meat should be halfway covered by the stock.

Cover the pot with a very tight lid. Cook in the oven at 300 degrees Fahrenheit. Leave it for two hours without opening the lid. The low heat turns the lamb very tender.

Take the meat out and strain the sauce. Boil the liquid until it looks like syrup. Pour this dark glaze over the soft lamb. Serve it hot with your favorite creamy side.