Peel and chop the onion and garlic finely. Rinse the parsley in cold water and let it drip dry. Cut it coursely and mix with the onion and garlic.
Pound the pork with a tenderizer. Distribute the onion-garlic mixture evenly onto the meat. Season with salt and pepper. Then roll the meat up into a ”sausage” and truss it tightly with the string. Boil water, salt and sugar in a pot and cool it off. Place the roulade sausage in the brine and let it soak for 24 hours.
Place the sausage in a pot of fresh water, beer, bay leaf, black peppercorns and the parsley stem. Bring to boil and skim off impurities.
Boil the sausage for 1 1/2 hours at low heat. Turn off the heat and let the meat soak in the brine until cool.
Now place the sausage in a press, either a roulade press or two steel plates with something quite heavy on top to squeeze the meat together.