From what I've read about temples and knowing what I do about kitchens, I really don't find "cook" an appropriate translation of tenzo. The only literal translation I've seen is "heavenly monk," but that's from Wikipedia. The tenzo is an officer of the temple in charge of the kitchen, this makes him by definition chef , which is the French word for boss. (also visible cognates: English "chief", or Spanish "jefe") His job is multi-faceted and I'm sure anyone who has served as tenzo would agree that they do more than just cook.
Most people have come to understand an abbreviated role of what it means to be a chef. They think all the chef is responsible for is coming up with the menu and taking credit for the success of a restaurant. This is only where it begins.
The day to day life of a chef is far more than that, a real chef at least. People think culinary students go to school to learn how to cook the classics and make stuff up. I've even worked in kitchens where the staff resented their boss because corporate policy gave them the title of chef even though they'd not made up the menu or been to school. In some restaurants, this position of chef is called the kitchen manager, and my training in culinary school is essentially for that purpose. While we do take cooking classes, we also take classes on management of people, product and money, purchasing, and safety and sanitation.
One of the things covered in most classes is the flow of the food. Purchasing is a little complicated so I'll leave it out, but food comes in the back door. The chef is usually responsible himself for checking to make sure everything he ordered is there and up to the standard it should be. (not all food purveyors are as reputable as they should be... but the same goes for some chefs. anything to make a profit) In a traditional temple, all this shows up in the form of offerings if it's not grown by the monks themselves so they don't get to be picky.
Dogen covers this in the Tenzo Kyokun:
"Without worrying about their quality, simply make the best of what you have. It is prohibited to show your feelings or say anything about the amount of ingredients."
"Even when, for example, one makes a soup of the crudest greens, one should not give rise to a mind that loathes it or takes its lightly; and even when one makes a soup of the finest cream, one should not give rise to a mind that feels glad and rejoices in it... Even when confronted with poor ingredients, there is no negligence whatsoever; even when faced with scanty ingredients, one exerts oneself."
Yeah, that's part of the whole accepting without prejudice and unattachment thing. They don't have customers that can vote with their feet about how the price of the food doesn't add up to the quality. There's a saying, "The mouth of a monk is like a furnace, Just as a furnace burns both sandalwood and cow shit without distinction, our mouths should be the same, eating rich and plain food as food. We should use whatever we receive." You can't put that on a wall to point at everytime a guest complains.
Another task layed out by Dogen for the tenzo is to mindfully count all the monks that need to eat and prepare just enough food to feed them and not have any left over. He lists all the places monks may be hiding to check so that nobody goes hungry.
In a professional kitchen, this is a little trickier. Until you've been in business for a while, you can't really predict how much volume (or business, in non-industry speak) to expect for each meal. There are a lot of factors to consider: day of the week, season, weather, holidays and other local events. While there isn't such a strong imperative on not having left overs and sometimes items do sell out, unsold product is loss of money.
These are just two things a chef and a tenzo have to deal with and there hasn't even been any cooking yet. There are other similarities such as how to treat food and such, but I can save that for another time.