enter the info on sw online babe, (the syns calculator tab on webby is on top right hand side) enter the nutritional info and it'l give you a result, it can be flawed at times, but thats usually with things including free stuff, which obviously unless your cookies are sprouting carrots, it should be 100% accurate.
i make my rice pudding with pudding rice, water and a dash of milk for a half a syn, and use loads of sweetner, its supposed to be nicer with using your hea milk allowance as the majority and topping up with water but quite frankly i wouldnt bother, as its not worth wasting my cheese topping haha xx