Please explain the sentence:

"He was too good a cook by half for this small restaurant."

Here's Cambridge's explanation for "too clever by half":

be too clever by half
to be too confident of your own intelligence in a way that annoys other people:
She was too clever by half - always correcting the teacher or coming back with a smart answer.

So your sentence means "he was far too good a cook etc..."
Thanks pieanne for your kind help.