Add ingredients to the batter to make the cake you want.
The Pioneer Woman suggests using one more egg than the recipe calls for for a moister cake or replacing water with milk for a richer cake
Sometimes cake chocolate isn't chocolatey enough. Adding liqueur to your cake mix boosts chocolate flavour in ways you didn't expect.
Bon Appétit recommends adding espresso, dark rum, or Kahlua to enhance the cake's chocolate flavour.
Since they're both Caribbean products with similar flavours, chocolate and rum should go well together
However, these liqueurs can be used in more than chocolate cake. You can make the Barefoot Contessa's chocolate cassis cake,
A Black Forest cake with cherry liqueur, a Caribbean rum cake, or your own recipe.