The black flesh of fermented kluwak seeds (aka keluwek or black nut) adds a very unusual and thick earthy base to meat stews in regional cuisines of Indonesia and Malaysia. It is particularly well known as a key ingredient in an intensely flavored East Java stew called Rawon, and in buah keluak pork and chicken stews in Malaysia. Fortunately for us in Philadelphia, this is yet another exotic ingredient that we can get locally at one of our several Indonesian grocers (light green points on my map of Philly Asian markets).
Kluwak seeds (see here for the wiki entry for pangium edule) are delicious as a base for savory dark stews. That said, the pale white flesh of the fresh nut is actually poisonous. It can only be consumed after the toxic effects are mitigated through boiling and fermenting in ash and banana leaves for 40 days. By that point, the flesh turns an oily dark brown. In bazaars of Indonesia, you can buy the fermented seeds, still in their dry, clam-sized oblong gray shells (see here for an image–as there are 6-8 seeds in a single fruit, the actual fruit must be huge!)
If you go to a Market in Indonesia, you can see people shelling the seeds, scooping the flesh out of the gray shells. The only kind available to us in Philadelphia is the seed-shelled flesh, vacuum packed in plastic (see left).
The freshly-shelled seeds have a much softer flesh. The shelf stable vacuum packed kind we have in Philadelphia are much more firm. To cook with the latter, first soak the flesh in warm water, let sit for 15 minutes or so and mash (I just use my fingers), much like the process for making tamarind liquid for cooking preparations.
In my experience, I felt some shell pieces and some tough bits that I thought might not be so nice in my soup. Because of that I chose to strain my kluwak sauce. Other Indonesian home cooks simply blend it all up with the other soup base paste ingredients (dried spices, shallots, garlic, shrimp paste).
Recipe: Black kluwak-stewed beef with rice – Nasi rawon
Nasi Rawon is a much loved go-to meal for East Java (and in metropolitan areas all around Indonesia). Many recipes can be found online, and the basic ingredients seem to be pretty standard. Here are some online recipes for comparison: from Singapore Local Favorites and Travelling Foodies. I found some nice video recipes too, but they are in Indonesian. That said, they are pretty easy to follow if you recognize the ingredients. Here is a video from of a typical Surabaya recipe from Resep Masakan, and here is an East Java news TV program from NET JATIM that includes a restaurant visit to a visit to a famous rawon restaurant in Surabaya (Rawon Pak Pangat). There they serve the stewed meat over rice as well as a bowl of broth separate for customers to pour over when they are ready.
Common accompaniments to this stew (besides rice) are salted duck eggs, mung bean sprouts, lemon basil, cucumber slices, shrimp crackers, and spicy sambal. I loved this stew when I sampled it in Indonesia, but I found the salty duck eggs overkill as the stew was already so intensely flavored. In my version below, I mellowed the accompaniment to simple hard-boiled egg and cucumber. I recognize that may be possible heresy.
This stew is pretty simple to put together, with the most hands-on time spent soaking and mashing kluwak and tamarind, and mashing the soup base seasonings. Below is an approximate list of ingredients and quantities I used. I had a cookbook reference point (Indonesian Kitchen: 300 popular recipes across the archipelago, by Yasa Boga, Gramedia 2015), as well as several web sources:
- Beef for stewing, about 2 lbs
- flesh from soaked kluwak seeds (I used the whole package above)
- 3-4 thick slices of galangal root (I used frozen)
- 3 lemongrass stalks, bruised (I tossed some green stalk into the soup as well)
- 3-4 salam leaves
- 3-4 kaffir lime leaves
- palm sugar
- tamarind soaking liquid (about 1/2 cup)
- salt to tasteFor spice paste:
- [Asian] shallots (about 6)
- garlic cloves (about 5)
- ginger (about 1 Tbsp)
- candlenuts (4)
- ground tumeric (about 1 tsp)
- coriander seeds (about 1 Tbsp)
- belachan (shrimp paste, about 1 tsp)
- Soak kluwak seeds and tamarind. Mash flesh and make thick liquids. If you use too much liquid, you can just use less water or stock later. See above images for soaking kluwak, and see images here for soaking tamarind.
- Dry fry coriander seeds and candlenuts and pound into a fine powder. Add chile peppers, salt, keep pounding. Add shallots, garlic, ginger. Pound to a paste. Finally mix with tumeric and belachan (see above).
- Prepare lemongrass stalks and galangal. Prepare kaffir lime leaves (see above).
- Heat oil in a pot. Fry spice paste mixture, lemongrass, galangal, kaffir lime leaves until fragrant. Add cubed beef. Stir it up good.
- Add in the kluwak liquid and the tamarind liquid. Add water or stock to cover the beef. Boil until meat is tender to your preference. For me, after about 1 1/2 hours my beef was starting to fall apart.
- Serve with rice, salted duck egg, cucumber, bean sprouts, shrimp crackers, sambal, etc. As mentioned above, today I chose mild accompaniments of hard-boiled egg and cucumber.