While the main focus of a site like Serious Eats is to share new recipes and techniques, the work of a baker isn't a relentless march forward into new territory. Those forays, breakthroughs in understanding and approach, are what make the job exciting, but a baker's day-by-day work is rooted in making smart use of existing knowledge, i.e., existing recipes.
So, while a certain combination may be presented as a single dessert—for example, a classic devil's food cake with chocolate buttercream, or a white cake made with toasted sugar and topped with maple frosting—using the individual components that make them up in other compositions can be a lot of fun.
It's easy enough to imagine swapping out one icing for another, but when you know how to scale a recipe for cake, the layers themselves can be adjusted to suit the occasion—for instance, you can make two layers of strawberry cake instead of three (for a smaller party), with the usual cream cheese frosting traded out for strawberry buttercream.
A mix-and-match combination like this can be further customized by garnishing—for example, a generous smear of creamy peanut butter in the middle of a two-layer devil's food cake (instead of a three-layer one) that's paired with a honey-banana frosting and topped with cocoa nibs and honey-roasted peanuts.
It's not just the finish and frosting that can be swapped in and out of the equation. The cakes themselves can be scaled into single layers for reconfiguring into new combinations, as in this Neapolitan cake of vanilla, strawberry, and chocolate layers.
This kind of dessert is admittedly a lot more work than a layer cake of a single flavor, but sometimes it's fun to flex those culinary chops and exercise a bit of creativity—whether for the personal sense of accomplishment alone, or to fulfill a craving of your own or that of a loved one on a special occasion. (Although, in the latter case, please do give yourself time for a practice run!)
It's the nature of cookbooks and blogs to present recipes in the context of a whole, complete dessert, but as bakers, we should remember that those ideas and images are serving suggestions at best, concepts we can strip down for parts. Especially for beginner and intermediate bakers, it's this type of creative thinking that will provide the most stable base for experimentation and personal expression, and help us neatly avoid the risks associated with reformulating a recipe if we don't have a deeper knowledge of all the moving parts.