Preparation / Directions:
Wipe the pork with damp paper towels, then cut into 1-1/2 inch cubes (the fat and skin may be left on during the cooking and removed later). Melt 2 tablespoons of the butter in a heavy pan or Dutch oven. Add the onion and cook until soft and transparent, then add the pork and cook, stirring, over medium heat until the raw meat color disappears. Season with salt and pepper, add hot water to cover, then cover and simmer gently (or bake in a 325F oven) for 30 to 35 minutes, or until almost tender. (The timing is important because the celery is to be added and cooked with the pork only until both are tender but not overcooked.)
Meanwhile, prepare the celery. Wash the stalks and scrape the heavy ones slightly. Cut each stalk once lengthwise (if large) and then across into 1-1/2 inch slices. (Use the leaves as well, if desired, but a few might be saved for a garnish or an accompanying salad.) Add the celery to pork and continue simmering 25 minutes until both are tender. Using a slotted spoon, remove the pork and celery and place in a serving dish, first removing and discarding the fat from the meat. Keep warm. Skim the fat from the cooking liquid, then add water or boil down rapidly to make to make 1-1/2 cups. Keep hot while you prepare the avgolemono.
To prepare the avgolemono, heat the remaining 2 tablespoons butter in a pan. Stir in the flour, and after cooking over low heat for 1 minute, gradually add 2 cups of the hot cooking liquid from the meat. Stir until the sauce comes to a boil. Meanwhile, in a small bowl, beat the two remaining egg yolks and add the lemon juice, droplet by droplet, beating all the while. Beat a little of the thickened cooking liquid into the yolk mixture, then add the yolks to the pan of hot liquid. Mix well and cook over low heat until thickened. Pour the hot sauce over the pork and celery, garnish with parsley or celery leaves and serve warm.
Note: Celeriac may be substituted for the celery. Use 2-1/2 pounds of celeriac, and peel, quarter, and cut it into 1/2 inch slices before adding it to the pork. A little scraped, diced carrot may be added with the celery.