The day before, wash the meat, pat dry and remove any fat. Cut meat into 4 pieces. Peel onion, cut into thin rings. Wash parsley and cut coarsely. Crumble bay leaf
Rub meat with thyme and laurel. Put it in the freezer bag with onion, parsley, peppercorns and wine and close it. Chill for at least 8 hours, preferably overnight. Turn once if necessary
Lift out the meat and pat dry. Sieve the marinade and set aside. Drain onions well. Peel, wash and thinly slice the potatoes
Season meat with salt and pepper. Fry in hot oil in a roasting pan all around, remove. Steam onions in hot frying fat for about 10 minutes, remove about half of them. Place the meat side by side in the roaster. Spread the potatoes like roof tiles and season with salt and pepper. Spread the remaining onions on top. Pour on marinade
Cover and braise in a preheated oven (electric cooker: 200 °C/recirculating air: 175 °C/gas: level 3) for approx. 1 1/2 hours (do not stir!). Remove the lid and braise for another 30 minutes. Spread butter in flakes on the potatoes. Garnish
Drink: spanish Red wine, e.g. Tempranillo Reserva 2000 by Baron de Ley