From Creamed Coconut

Creamed coconut can be bought from many grocers and supermarkets, and also from health food stores. It comes in compressed dry white slabs, looking like half a pound of lard. You can use it as a kind of ‘instant santen’—but only in those recipes (e.g. Sambal Goreng) where santen is added at the end, after the main process of cooking is complete. Simply cut off a chunk from the slab and put it in the pan; it will melt, exactly as butter does. If you find, in almost any dish, that your sauce is going to be too thin, this is the easiest and quickest way to thicken it at the last moment.