First, allow the butter dissolve in a good-sized saucepan on medium high heat.
Place the lamb in your pan, and cook it until it browns. Leave enough room in the pan for other ingredients. Remove the lamb from the pan using a slotted spoon and set aside.
Place turnips, carrots, celery, and onion into the saucepan. Fry veggies for three minutes, mixing them often, until the onion becomes transparent. Return the lamb to the pan and add thyme.
Then take a pinch of flour and gently distribute it on the lamb and the vegetables. Bring the stew to low heat for 3 minutes, mixing stew often, and allow the flour to cook well.
Pour in cold stock or water, and set the heat on medium high, allowing it to boil.
Next blend in the tomato paste, and add salt and pepper. Keep the lamb stew covered on low heat for 40-55 minutes, or as soon as lamb is easy to cut.
After leaving the lamb to soak in the juices, place the potatoes in a pan of salted cold water. Bring the potatoes to a boil on high heat for fifteen minutes.
Drain out excess water and then mash the potatoes with a potato masher. Mash in the butter, egg, yolk, salt and pepper. Once the ingredients are mixed together, place them in a pastry bag with a big star tip.
Preheat your oven’s broiler and arrange the lamb in a large baking dish. Pipe the potatoes onto the lamb mixture in a latticework pattern. Set the dish six inches below the broiler element and cook until the potatoes are browned.
