Ingredients in the Netherlands are not always easy to come by. For example, you can find baking powder at your local AH (Albert Heijn) but if you want more than what's in a tiny package, you can go to Rohit, the Indian Store Supreme (Okay, that is my name for it). Here is the location in google maps.
For items like maple syrup, 'Great American Marshmellows' and Rice Krispies, check out Jumbo in Veldhoven. The first aisle in Jumbo has lots of great American products including cake mixes, brownies, and other ethnic items like hoisin sauce.