Can you use cake batter for cupcakes and vice versa? A lot of people have asked me that, and the short answer is: sure thing. However, there are a few things to remember about refrigeration, shelf life, and baking time between the two options... Cupcakes have a shorter shelf life due to their compactness. Since they have a smaller surface area overall, they'll dry up faster. So if you need to bake a cake ahead of time, you can bake it up to three days ahead of time, wrap the individual layers well in plastic wrap (unfrosted), and at least freeze it (never refrigerate baked goods for extended periods; the slow wafting of cold air in your refrigerator at a constant rate dries up baked goods like the Sahara). Frosted matter can and should be refrigerated though, especially if the frosting is dairy-based (traditional buttercream). Wilton, Duncan Hines, and Pilsbury frostings are shortening-based, and so when frosted, cakes and cupcakes can remain at room temperature.
Additionally, the general timeframe for baking cupcakes is 18-22 minutes, depending on your oven (whether it bakes hotter than most, which some people do experience). You definitely can't bake cupcakes for as long as you do a cake. Also, you should try to bake and decorate cupcakes over a 24-48-hour period and then make sure they get consumed shortly thereafter. Like that's ever a problem for most people. Who doesn't love a cupcake?
Clockwise from top: vanilla with vanilla buttercream and fondant flower with silver dragee; carrot cake with ginger cream cheese frosting and fondant-and-buttercream carrot; red velvet with cream cheese frosting and white chocolate disc; lavender lemonade with lavender-lemon buttercream and dried lavender blossoms.