I have buyed this spoon online indeed. I was checking the silversmid.
Dutch goldsmiths' and silversmiths' marks and names prior to 1812 by K. A Citroen
But in this documentation it is not mentioned that the initials are joined (this is the only documentation that I and the seller could find). I was hoping that somebody may be have documentation that clearly describes this hallmark. I have added 2 more photos: