Bake the puff pastry according to package directions. Once cool (and, ideally, stale brittle and dried out), break the pastry up into small pieces and put in a 2 quart casserole.
Preheat the oven to 425F.
Toss on the raisins, slivered almonds, and coconut chips. Dust with sugar and drizzle on the half and half and milk. Be sure to spread it evenly over the entire casserole.
Bake until the milk is bubbling and the top is browned. This could be anywhere from 15-20 minutes and will depend on how dry your pastry is, how browned it got in the first cooking and so forth. Just keep a keen eye on it.