Contrary to one of the previous reviewers, I've had the pleasure of trying poffertjes in many…read morelocations, so if not an expert, I'm at least an experienced enthousiast. I can say that these are the best I've ever had (although I may be biased; I come here since the age of 4, or thereabouts). The menu is not long, basically it is poffertjes (plain, wirh rum, ginger or Gran Marnier), dutch waffels (thinner and more crunch than Brusselse or Luikse) and drinks. That's all you will need, though.
The enormous poffertjes hob is impressive, the waffel oven is beautiful. As is the "kraam" itself (at least from the front and inside). Worth a visit in itself.
It is correct this place is not open all year round, between april and september you are in the clear, though (summer, basically). I believe they open mid april and close mid september.