Just write it like any professional letter. If you include more than one or two “marketing words” it will go into a spam filter.
You may have people recommend a pitch-specific style or format, but generally speaking, that stuff is antiquated today. People under 50 prefer that you just communicate with them like actual humans. They will spot boilerplate. Be professional, but also be conversational, and be brief and to the point and no BS.
If your recipients are authors/writers, the above is doubly true. They will recognize and be wary of wordplay, no matter how well-intentioned. If you are real and down to earth you will likely get a better result.
If your recipients are younger than you, do not talk down to them. Actually, do not talk down no matter what.
Try to express the tone of your brand. If the chef is very upscale, try to express that. If very homey, try to express that.
You might start by making a point-form list of what you want/have to say, then expand that into a nice professional letter.
Production-wise, email is its own medium like Web or TV or radio. You have to learn some email-specific principles in order to avoid many common pitfalls (like using marketing words and ending up in a spam filter.) So lookup commercial email production guides. There are lists of words not to use, guidelines on how to use images and reasons not to, how to choose a format, how to do branding and layout.
There are also laws not to break: