Set your oven to 180ºC to warm up while you prepare the stew.
Melt the butter in a large frying pan over medium heat and brown the lamb chops until nicely colored, then take them off the pan and keep aside.
Peel the onions and carrots, slice them thinly, then cook them gently in the same pan for about five minutes until softened, then transfer them to a bowl.
Pour a small wineglass of water into the pan to loosen up any browned bits, and let it simmer for five minutes to capture those flavors.
Slice the potatoes after peeling and arrange half of them in an even layer in a large casserole dish, seasoning well.
Layer on half of the softened onions and carrots, add the browned lamb chops, fresh thyme sprigs, and bay leaves, seasoning once more.
Spread the remaining onion and carrot mixture over the lamb, sprinkle the pearl barley evenly, then layer the rest of the potatoes on top.
Pour over the deglazed liquid from the pan and add 500ml of water.
Cover the casserole with a lid or foil and place it in the oven, baking for one hour and a half until the meat is tender and the potatoes start to crisp up around the edges.
Remove from the oven and serve your rich, warming Irish stew hot, perfect for sharing.
