A thick syrup, heavier and more robust than maple syrup, invented and used primarily by the Dutch. Close to molasses in consistency, and very dark. Frequently poured over pannekoeken (thin, large pancakes), poffertjes* (dollar-sized mini pancake puffs) and flensjes (crepes), this treacle adds an authentic touch. It can be added to both sweet and savory foods. It is generally made with a sugar base, usually brown sugar or cane sugar. Stroop-ish substance can also be found sandwiched in between layers of wafer-cookie in the form of stroopwafels. In North America, stroop is easiest to find in either a special pannekoek restaurant, or online/mail-order.
Rhymes with 'cope'
The word "stroop" is derived from the arabic "sharAb", meaning a drink made of syrup. The word "syrup" is derived from the same (Latin: syrupus), and both are thus related to "sorbet" (sherbet). Sorry, I know it's fun to say "strewp".
Stroopology
The Lower Mainland of British Columbia has a chain of restaurants called De Dutch Pannekoek House that serves delicious pannekoeken in a wide variety of flavours, authentic and local alike. Delicious. Stroop is an excellent topping on these pannekoeken for its sweet-but-not-overwhelming flavour. While maple syrup has a tendency to overwhelm what's being eaten with its own flavour, stroop complements pancake-type foods' own flavours and textures nicely. Furthermore, the traditional way to eat a pannekoek calls for rolling the giant cake into thirds, like a letter for an envelope. This makes the cake kind of rounded on top, meaning that stroop, with its thick constitution, will stick better and not run off. My personal rule of thumb: if it's got interesting flavour and/or texture of its own, go with stroop. Otherwise, maple syrup's flavour might be more appealing, depending on what one is accustomed to.
Disclaimer: while I have had *truly* authentic pannekoeken in Amsterdam, my main experience is in the Great White North, and so IANAE. (De Dutch Pannekoeken are very good and also very close to what I've had in Holland.)
*Although I have never heard of serving stroop over poffertjes, one recipe site offered it as a suggestion.
Sources:
Discover... traditional Dutch foods. "Beans with apples and pork." May 21, 2003. <http://www.godutch.com/cooking/893beans.htm>
Merriam Webster Online. "Syrup." May 21,2003. <http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=syrup>