Spike the pork with the halved garlic cloves and rub with salt and black pepper. Make a marinade of soya sauce, honey, mustard and oil and brush the pork neck thoroughly. Wrap it in foil and leave in a cool place to marinate for about 12 hours.
Remove the foil and sprinkle it with the remaining seasonings - rosemary, savory and cumin. Transfer it to a greased tray and pour in 4/5 cup (200 ml) of beer. Cover it well with aluminum foil and put it to bake in a preheated oven at 428°F (220 °C). Once the liquid in the pan comes to a boil, reduce to 356°F (180 °C) and let it bake for a little over 1 hour.
Shortly before the meat is ready, take it out and top the peeled and sliced potatoes and butter cubes. Top up with another 2/5 cup (100 ml) of beer and return it to bake until ready.