Cut the lamb meat into large portions and rub them well with the paprika, salt and oil. Sprinkle with chopped spearmint and leave as is for 20 min. to flavor.
Chop the onions in the meantime and pour them in a platter or tray, pour on a little oil, sprinkle paprika, white pepper and salt.
Place the lamb portions on top and pour in water but not too much, don't submerge it.
Cover with aluminum foil and bake in a preheated 374°F (190 °C) oven.
Optionally, after 1 hour you can remove the foil and sprinkle a little rice. If not, leave it covered and remove the foil only for the last 5 min. to crisp.