This pie makes excellent use of leftover short ribs (a rare occurrence!). It’s ideal for preparing in advance: fill the gratin dishes with the ribs a day ahead, then top with freshly made mashed potatoes just before baking.
Short Rib Shepherd’s Pie
4 beef short ribs, each 2 1/4-2 1/2 lb.
Sea salt and ground pepper
2 Tbs. extra-virgin olive oil
1 large onion, chopped
2 celery stalks, chopped
6 cloves garlic, crushed
1 carrot, chopped
3 1/2 cups dry red wine, such as Syrah
3 bay leaves
1 Tbs. fresh thyme leaves
4 cups beef stock, or as needed
1 1/2 lb. Yukon gold potatoes, peeled and quartered
1/4 cup milk
4 Tbs. unsalted butter
1 egg yolk, beaten
Season ribs with salt and pepper and refrigerate for at least 6 hours or up to overnight. Bring to room temperature and season again wtih salt and pepper.
Preheat oven to 350 degrees F. Heat a large saute pan over high heat until hot. Add olive oil and heat until shimmering. In batches, sear ribs on all sides, turning as needed, until well browned. Transfer to a Dutch oven. Pour off all but 2 tablespoons fat from saute pan and return to medium heat. Add onion, celery, garlic and carrot and saute until beginning to caramelize, about 5 minutes. Add wine, bay leaves and thyme, raise heat to medium-high, and boil to reduce wine by half. Add stock, bring to a boil, and pour contents of pan over ribs. They should be just covered with liquid; add stock as needed.
Cover tightly and braise in oven, adding stock as needed to maintain liquid level, until a fork slides easily through meat, about 2 1/2 hours. Skim off any fat from surface, let ribs cool in liquid until they can be handled, then remove ribs from pot and pull meat from bones. Shred meat into bite-sized pieces, return to Dutch oven, and discard bones.
While ribs are cooling, in a saucepan, cook potatoes in boiling salted water until tender, about 15 minutes. Drain, dry in pan over low heat, then pass through ricer back into warm pan. In a small saucepan, heat milk and butter until mixture is steaming. Pour into potatoes, add egg yolk and fold to mix well.
Raise oven temperature to 400 degrees F. Transfer contents of Dutch oven to a 9-by-13-inch baking dish or divide among individual gratin dishes. Cover top(s) evenly with potatoes. Bake until topping is golden, 35-40 minutes. Serve at once. Serves 6-8.