“Cake is good” is a statement that needs no qualifying, no couching, no parenthetical asides. Cake does not need me to hype it up. Cake does not need a PR firm. Unequivocally good things, such as cake, should be protected and cherished and, in the case of cake, kept moist for as long as possible.
Frosting, icing, and fondant form an essentially hydrophobic barrier around the cake, preventing moisture from leaving its plush and tasty layers. Once you cut into the cake and remove a slice, though, you remove this protective barrier and (literally) open the cake up to moisture-leaching air, which can result in dry cake.
There are a few ways you can prevent this. America’s Test Kitchen recommends storing the cake with a peeled apple under a cloche on a cake stand. The apple adds moisture to the environment, acting as a cake humidifier and preventing the cake from drying out.
But fruit can attract flies (even under a cloche), and I’d rather eat my apples. Rather than get fruit involved, you can take a cue from pastry chef and TikTok user austrianwithwuff, and use an elegant piece of parchment paper instead.
Much like frosting, icing, and fondant, a sheet of parchment paper (or wax paper, or plastic wrap) acts as a hydrophobic barrier, keeping moisture inside the beautiful layers of your cake. I actually think wax paper would work better than parchment, as the former is even less permeable than the latter.
Just cut the parchment paper (or wax paper, or plastic wrap) to roughly fit the area of exposed cake you need to cover, then fold and press it onto the exposed cake. Store it under a cloche for extra protection, readjusting, replacing, and/or re-cutting as needed to keep the newly exposed cake covered with each slice.
