Question:
if someone who is a chef is he allowed to read cookbooks on shabbos even if he only does it because its gives hi oneg shabbos
Answer:
Thank you for your question.
A chef should not read cookbooks on Shabbos because for him it is business related material (sharey hedyotos). Although he is reading it solely for enjoyment, and other people may read them on Shabbos, however since cooking is his business, for him it is business related.
Best wishes
Sources:
Shmiras Shabbos Khilchoso 29-48, 49 ftnt. 124.