Mix the parsley and garlic together, then blend in the butter . You should get a smooth spreadable paste. Season with salt and pepper.
Spread the parsley paste onto each veal escalope. Next, put a slice of ham on each escalope and add some sliced egg into the middle. Roll each piece of meat tightly and secure with cooking twine or skewers.
Heat up a couple of tablespoons of olive oil in a pan or a pot ( that will accommodate the rolls and the sauce). Add the chopped onion and celery and fry until they start to soften.
Dust the rolls with a thin layer of flour and add to the pan. Brown them on a medium heat on both sides. Next add the wine and let it boil and reduce a bit. Then add the broth, reduce the heat, put the lid on and gently cook for a minimum of 40 minutes ( if the veal escalopes are quite thick you may need to allow more time).
Once the rolls are cooked, remove from the pot and blend the remaining sauce in a blender.
Return the sauce in the pan and carry on cooking until the sauce starts to thicken.
Once you are happy with the consistency, season with salt and pepper. Return the rolls back into the pan with the sauce, warm up and serve.