The Zebitz Vikings share the recipe for:
Pit baked pig with salad and flatbread
2.5 kg pork neck/shoulder
Salt for seasoning
Optional: herbs like thyme, garlic
For wrapping use lots of large leaves like e.g. turnip, plantain or dock leaves, and tie with string. The Zebitz Vikings wrapped the meat in salt dough. It works fine, but isn't historically accurate.
To make the cooking pit, dig a hole about 50 cm deep and line it with large stones. Light a fire on top of the stones and add more large stones to the fire. Let it burn for about 3 hours to thoroughly heat the stones. Once the fire has burned out, you end up with a pit full of hot coals and stones.
Use a piece of wood or another tool to spread the stones over the coals. In this case where the meat is wrapped in dough, it can be placed directly in the embers. If you use leaves for wrapping, place the meat onto hot stones which have first been covered with wet grass. Cover the meat parcel with more hot stones. Seal the pit oven by covering it with turf.
Leave the meat to cook. This roast of 2.5 kg in salt dough needed 5 hours of slow cooking. If the meat is wrapped in leaves, allow 1.5 hours per kilo of meat. The temperature in a pit oven can reach about 200 degrees centigrade, which kills the soil bacterias.