Kuri manju is my favorite manju snack, but there's no Japanese bakery where I live. So I have to improvise and I make something similar. I cheat and I don't use shiro koshian and there's a good reason for this. I can't make very nice shiro koshian and I can buy regular koshian at the grocers. The result is not exactly like kuri manju, but it's close. I always use an egg wash and sesame seeds on the top, because it makes the manju beautiful and since I'm pretending not to make traditional kuri manju, it's okay. Don't expect this to be like a chinese filled bun that you'd find at a dim sum restaurant. This dough is more of a soft shortcrust type. I think you could fill this with other softer (but not liquidy fillings), but I'm having a hard time imagining what those would be (sorry, it's late here). Prep time doesn't include the time the dough MUST sit in the fridge or freezer.