Asem= tamarind was similar that was sour it seems; normally was used as much in Indonesian cooking as addition of sour taste.
I just remembered last our vocation in Solo, we went to my grandma's home and she served exotic menu there. We ate asem asem daging with warm rice as companions really it was great food. After we had finished our lunch immdiately i asked to her how to prepare and for sure its only simple :)
-meat 1/2 kg, boiled until tender and add salt
-green beans 100 gr, cut into small pieces
-tomato 1 big size, choped
-tamarin 1 inch
-bay leaves 2
-onion 1 big size, choped
-garliv 3 cloves, crushed
-salt and sugar for taste
-soya sauce 1 spoon
-green chili 3 pieces, split into two
-dried red chili 2 (optional)
Heat little oil in a pan then saute garlic and onion for 2 min, add green chili and dried red chili, saute for 1 min. Then add tomato choped and bay leaves the same time add water also.
Add boiled meat and green beans, let it cooked for one more time. Add all the seasoning and the end add soya sauce. Cooked and let water reduced. Served with warm jasmine rice.