Early in my career when interviewing for a job I was asked to cook an egg over easy, I was asked to finely dice an onion. I have also been asked how I would make Beef Bourguignon beginning to end or the ingredients in a tarragon reduction for Sauce Béarnaise. It was a time when the intuitive employer could tell all they needed to know from the way these simple tasks and questions were answered. Many jobs were offered just by the recommendation of a reputable chef that you had previously worked for, knowing that if you could do well in "his" kitchen you would do well in there's. (sorry for the use of "his", but these were little to no female chef's at that time)
In the last 25 years, having a Chef or Cook do a tasting, has become the norm. There is an enormous amount that can be learned from experiencing the taste and presentations of how we cook, and generally we accept that this is what it takes to be offered the position; after all, "It's what we do." I have done the mystery box tasting with specific ingredients, I have been turned loose to use what ever products that I could find in the hotel, I have provided menus according to the criteria set by the potential employer and I have equally been part of the team of tasters, as been the one preparing the tasting. It is a lot more enjoyable to be tasting the results than preparing them. It is even better when your future employer solicits you at your existing job where your tasting was the meal that they just experienced.
Even for the Chef doing the tasting interview their is much to be gained by spending time in a potential new kitchen. Is the kitchen clean and safe? What is the quality of the cooks & stewards along with the turnover rate? What is the quality of the vendors and products used? Who is going to be supervising you, can you get along? Your inclusive experience leading up to asking yourself if you can see yourself in this kitchen and doing well, and is it possible to add your systems in place to achieve the level of results that you would be proud of long term. Or..... you have no money, no job, and you will take this job no matter what if you get it, while you look for a position that you would be happier in!
Being thrown into a busy kitchen on a little obscure table space without a stove or oven near you and a short time to create 100% of your Mise en Place so that you can put dishes together that reflects the best of who you are, is a very tough task under the best of circumstances. Things are rarely in your favor, and it's not like you can make excuses to the tasting group as to why your food did not turn out as well as you have done it before. In a recent experience I was asked to provide a list of ingredients for a tasting. Upon my arrival the list was incomplete and none of the quality products that I requested were present. They had made substitutions with their lesser quality in-house products, and asked me to work with those! How do your say to the tasting group that this dish would be much better if you had provided me the products that I requested? Well you don't, just like you don't make excuses to diners in your restaurant.
My advice for chef's and cooks doing a tasting interview would be to choose signature dishes to prepare that you confident about, and save a very small part of the tasting for being creative on the fly. Throw a couple extra dishes in that were not asked for, like an amuse, a bread or your favorite dessert to show your versatility. Don't let the pressure overwhelm you because your not in the comfort of your last kitchen, handling pressure with a smile is part of the test. Embrace the moment and attack the tasting as an opportunity to show what you love to do.