This easy chocolate coffee mug cake is the perfect single‑serve dessert when you’re craving something sweet but don’t want to bake a whole cake. Ready in just 5 minutes, this microwave mug cake is fluffy, rich, and customizable with chocolate chips, espresso powder, or your favorite frosting. Enjoy it straight from the mug or top with ice cream, whipped cream, or caramel drizzle for a quick indulgence.