MELT 2 TABLESPOONS BUTTER in a small saucepan over medium heat, add the celery and onion and cook, stirring often, for 5 minutes. Sprinkle with flour, and cook, stirring constantly, another minute. Remove from heat and scrape mixture into a mixing bowl to cool. Add the lamb. Wash the potatoes but don't peel them. Shred them on the shredding blade of a food processor, or coarsely grate them by hand. Add the potatoes to the bowl and mix well. Season to taste with salt and pepper. Melt 1 teaspoon of butter in a 6-inch non-stick frying pan over medium heat. Add about 3/4to 1-cup of the hash mixture, or about a 2-inch thickness. Cook without stirring or moving the hash for 3 minutes. Flip the hash, which will have formed into a patty. Reduce heat to low and continue to cook another 5 minutes. Repeat with the remaining mixture. As each hash patty is done, transfer to the oven and keep warm. To serve the hash, place 2 poached eggs on each serving.