The History of Kastengel and Nastar
During Idul Fitri or Lebaran, Indonesian moslems encounter an endless supply of foods (YES!); in Java, popular Lebaran dishes are of course ketupat and the opor ayam. But the strange thing is there are European snacks namely kastengel and nastar circulated heavily through online and traditional shop during Lebaran. Well, this is this the history:
Kastengel comes from the Dutch "kaas / cheese" and "stengel / stick" hence the whole words mean "cheese stick". In Netherlands, the original kaastengels is indeed stick-like; it is thin with 15cm length. The primary ingredients of kaastengels include gouda cheese (cheese that red skin), cheddar and edam, and also puff pastry. Kaastengels are usually served with soup and salad during Christmas or local holidays.
Being colonised by the Dutch for hundreds of years, the kaastengels were popular among the priyayi (noblemen) of Indonesia. For some reasons the original kaastengels dough was changed from its original thin and long form with crispy texture to a cookie-like that is tender in texture with more flour used to replace the cheese -cheese was expensive at that time. At first kaastengels is still presented as a complement to soup and salad at rijstaffel dinner but slowly turned into a cookie.
Nastar is also derived from the Dutch "ananas / pineapple" and "taart / tart / pie" which we can conclude on its own meaning. The difference with kaastengels is that nastaart was created by the Dutch in Indonesia. In the past, pineapple was not available in Europe or North America as it was only exist in tropical regions. In the Netherlands there are apple pie or berry. And nastaart is a form of effort to make pie with pineapple stuffing because apples and berries were hard to find in Indonesia.
So why kaastengels and nastaart are more popular during Lebaran than Christmas? Basically it's just because the priyayi were predominantly moslems than christians. Both cookies were using expensive ingredients affordable only by the rich, for the less fortunate people, they celebrate to celebrate Lebaran with ketupat and opor.