Arni Kapama (Lamb Stew)

2 1/2 lbs. stewing lamb, cut in cubes 
1 1/2 lemon 
1/2 cup butter 
2 lbs. chopped tomatoes
2 tsp. salt
1/4 tsp. pepper
small piece cinnamon (optional)
1 Tbsp. sugar (optional)

Sprinkle lemon juice over meat and leave for 1 hour. Heat butter in a
frying pan and brown meat. Transfer to large saucepan. Put tomatoes in frying pan. Add salt, peeper, cinnamon and sugar. Boil for 5 minutes and add to meat. Simmer covered for 2 hours. Serve with potatoes, rice, macaroni or spaghetti.