Dried Out Cake in Display Case
Another suggestion: cupcakes....gourmet cupcakes of course. Or you can use acetate cake bands and display mini cakes very decoratively without them drying out, like so:
Be sure to brush each cake layer with liberal dose of a complimentary flavored simple syrup.
Once a cake is cut its time is very limited. Press plastic wrap or parchment paper directly onto the cake.... and make sure the pretty uncut side faces out. Other then that.... there is not much you can do to prevent it cakes from drying out.... So dont make to many in advanced :)
Doing rectangle slices of Cake, then coating with a light layer of white chocolate or chocolate coating works well. Decorations add the flair you need.It will prevent the air from hardening your cake. We also use acetate between the slices, which retain the show of the layers. Since we are in limited space in the display case, we find we can maximize the selection going this way.
This sounds tacky, but it's another arrow to add to your quiver.
Clear plastic clamshell boxes. They're airtight and display well. And besides, the counter staff can't make a mess of them like they do with a whole sliced cake.
Mind you this won't work for every setting. It's great for the after dinner crowd who want a slice of cake to enjoy at home. I used to put in some nice chocolate decorations and fruit like physalis/cape cod gooseberries, that keep forever and still look classy. I even used to have a "stash" of "HappY B'day" chocolate ettiquetes and candles for the counter staff to include if needed.
A lot about the drying out depends on the fridge itself. Gravity coil fridges are the worst, and the cheapest type. Re-apropriated/repurposed soft drink fridges are almost as bad with a fan on top blowing air across. The better cases have fan circulation, but much gentler, and cakes don't shrink and dry out as quickly.
Another thing to do is individual portions.. mousses, tirimisu, etc. These can be completely encased in clear or patterned cellophane wrappers, and usually hold up for two days. I find If I make a glazing ganache of 80 gr 33% cream, 100 gr of 70% couverture, and 25 gr corn syrup, the ganache shines nicely and won't crack for at least 4 days under ideal conditions.