Millennials generally are still lucky enough have their mothers in the picture, and maybe even their grandmothers, even if those relatives, at whose dinner tables presumably a lot of those nostalgic memories were made, live some distance away.
First alternative - have the chef call the person who originally made the dish and find out exactly how they made it.
Second alternative (admittedly a very high end one and probably not viable within a 24 hour timeframe) - Buy (or find a loaner FD in the local area for or someone who could take a prepared meal and FD it for) a freeze-dryer each 'mother' or 'grandmother' (if they are not local) and have them cook the exact dish their child or children are craving, freeze-dry it and mail it to the restaurant, which will reconstitute it and present it as though it was freshly prepared for that client exclusively.
Third alternative - send the kid home to Momma to eat the dish once in a while - and tell them while they are there to WATCH what is going on in the kitchen (get off that cellphone and stop texting) and listen to the kitchen wisdom of their elders before bringing in a recipe that they themselves have no idea how to reconstruct.
It is probably more difficult to feed the elderly with any of the above strategies since the people whose meals they remember fondly are probably well gone by now. But, take heart because as long as most stuff is bland and overcooked, the current very elderly generation will probably not take much issue with it. Now, when MY generation gets to that point I am hoping that you would not be able to please us as easily - since many of us, while we may have grown up in the post war era, when canned soups and convenience foods, and overcooked meats and veg were quite the rage, have broadened our culinary tastes and horizons considerably and it will be much more challenging to recreate our favorite meals as we fade into the horizon.
At any rate, I think you are going to have to limit the scope of this backwards 'restaurant' if you want it to be viable because as I said you cannot be all things to all people. You will have to choose a class or two of favorite meals that millennials (your primary target market for now) generally like and offer as many varieties of those as you can and/or use a basic burger and offer truffles and fois gras and sauerkraut and 50 varieties of cheese, etc. as toppings on x number of different breads. Are they the 'hamburger' (but 50 different ways) generation? Or are they inspired or nostalgic for a specialty pizza of some kind? Find what has made these kids MOST nostalgic, in general, if possible and work from there to refine your boundaries (which you have to have to be financially viable at all).
You can expand the options that you feel competent to prepare as time goes on if the concept flies at all. Use the incremental approach and just feel your way from a basic, well defined, 'possible' within the other constructs you have set for yourself (price point and time being significant ones) to where you want to go. Doing it all from day one would indeed prove disastrous - but then we already have pointed out why that would be.
