Hi Paul,
It is indeed a Dutch spoon made by H.Hooijkaas.
They still excist (The silvertown of Schoonhoven).
http://www.hooijkaas.nl" onclick="window.open(this.href);return false;
The spoon is not silver though, it's silverplated.
The '90' mark indicates 90 grams of silver used to cover 12 dining spoons and forks.
Weird mark on a small spoon but it indicates a bit of the thickness of the silvercoating.
It's hard to say anything about the date as there is no official dateletter on silverplate in Holland. But they are in business since 1874.
I forgot what the crownmark means, I believe it was more for decoration than anything else.
p.s.: I'm sure that when you send them an e-mail, they will provide you with information from their archieves (info [at] hooijkaas.nl).