Please tell the chef it was delicious.

Literal

Head-chef [to-に] was-delicious [quotative-と] convey [please-ください].

料理長 ('head chef, kitchen master') — 料理 ('cooking') + 長 (suffix for head/leader). お伝えください is the respectful お+stem+ください form of 伝える ('to convey'). An elegant restaurant compliment.