Translation:You played like a poffertje without sugar.
It was a real thing at least one Dutch person said! If you look at the link Mara gave, above, it's a quotation from a Dutch football coach about the performance of one of his players! Whether it became a cult phrase that passed into the language, I don't know. But I assume that if you are a keen fan of Dutch football, you'd recognize the reference.
I (native Dutch) have to agree: I have never heard this expression and I don't think it was ever used after that one occassion. I had to google if and when it was used...
However, as SebastianChw pointed out, it's pretty intuitive... and pretty funny at that... Do note: it's not a common expression or objective description! It will most likely be considered an insult (although mild), so don't randomly use it when speaking directly to somebody... ;-)
I'm not sure I entirely agree it's pedantry in this case. From what I can gather - bearing in mind my knowledge of the subject is derived only from this skill and the contributions of other users - "pancakes", in the English-speaking world, does not accurately describe "poffertjes". In fact, there is no exact translation, so you either leave it in the original Dutch - which is accepted - or you must qualify it in some way, to show you don't mean just an ordinary pancake. "Tiny" is a reasonable qualification. I notice the BBC chooses to call them: "baby pancakes". http://www.bbcgoodfood.com/user/369160/recipe/dutch-poffertjes-baby-pancakes