Ingredients
500 g (=1.1 lb) lean pork
5 onions
1 l (=4.2 cups) kefir
salt, pepper, other spices to taste

Directions
Cut pork into cubes (5-6 cm (=2 inches)).
Finely chop three onions.
Place a layer of pork in a saucepan, follow with a layer of chopped onions. Repeat. Season each layer with salt, pepper and other spices. Pour in kefir and refrigerate for about 24 hours.
Slice remaining onions. Thread pork cubes onto skewers alternating with onions slices. Baste with marinade while grilling.