A matter of some consequence.

One of the big questions of our time, according to correspondance in my paper, appears to be whether it is teaspoonfuls or teaspoonsful? Seems simple to me - assuming you are using, and then refilling the same spoon, then it is one teaspoonful, followed by another teaspoonful and so on. So it's teaspoonfuls. If you're using a succession of spoons on the other hand (but why would you?), then it could certainly be argued that it's teaspoonsful. Ah, these deep philosophical questions!