This single-serving keto mug brownie is the perfect answer to a sudden craving. It’s rich, fudgy, and ready in under two minutes. We’ve balanced this recipe to be perfectly low-carb, using almond flour and a sugar-free sweetener to keep net carbs incredibly low. The addition of instant espresso and a hint of cinnamon creates a deep, complex mocha-spice flavor that makes this simple treat feel truly decadent.