Pork with celery in egg/lemon sauce

One of the most popular and delicious pork dishes around Greece during the Winter months

Ingredients (for 4 people):
1Kg of pork, cut in portions (leg or shoulder)
1 large onion, finely chopped
1/3 bunch of flat-leaf parsley, finely chopped
1 tea-cup of olive oil
2 tea-cups of water
1 large bunch of celery, roughly chopped (buy with the leaves and the root on)
salt
pepper
1 large lemon, the juice
1 large egg, separated
2 tsp of cornflour (cornstarch)-optional

Method: 
Wash, peel and roughly chop the celery, its leaves and its root.

In a large pot warm the oil in medium heat and sauté the onion along with the parsley stirring with a wooden spoon. Add the meat and sauté until it gets nicely browned on all sides.

Pour over with the water and add all the celery parts. Season with salt and pepper, turn the heat to low, cover with the lid and leave the food to cook slowly for about 2 hours, until meat and celery are tender. Then switch off the heat but leave the pot on the cooker hob.

In a large bowl beat the egg whites with a whisk until they look like a meringue. Add the egg yolks, the lemon juice and keep whisking until they blend.

Carefully, using a ladle, pour slowly into the egg/lemon mixture some of the hot juice of the food, whisking vigorously at the same time so to prevent the eggs from curdling. You might need to add 2-3 ladlefuls of hot juice. *** If you prefer a thicker and more velvety type of sauce, dissolve the cornstarch into the lemon juice before you add it in the egg mixture.

Then pour the egg/lemon mixture into the pot and, holding by the handles, gently shake it in a circular mode so the "avgolemono" sauce coats the food evenly.

Serve immediately along with fresh rustic bread and feta cheese.