Tempeh (and often tofu) simmered in coconut water, palm sugar and spice until the liquid is gone, then fried until dark and sticky.
What makes it tempeh bacem
Simmered in coconut water with palm sugar, coriander, galangal and salam leaf.
Cooked until dry, then fried.
Sweet first, savoury behind.
Where it comes from
Bacem is a Central Javanese way of cooking — slowly, in sweetened, spiced liquid until it's all taken up — and tempeh and tofu are what it's most often done to. It's found on every warung counter in Yogyakarta and Solo, and alongside gudeg.
The first cooking seasons it through; the frying afterwards caramelises the sugar on the outside. It keeps for a day or two, which is why it's so often made in quantity.