In a microwave-safe bowl combine the chocolate chips and butter and heat at full power for a minute.
Remove from microwave and stir until chocolate and butter is completely melted.
Whisk in the sugar, flour and egg.
Pour batter into large, greased mug (at least 14-18 ounces) and heat at full power for two minutes.
Use a butter knife to loosen brownie from sides of mug and invert onto a plate. . .or just leave it right in the mug!
Surround with some extra chocolate chips, top with ice cream and enjoy.
Notes
Microwave Wattage: Microwave cooking times can vary based on the wattage of your microwave. If yours has a higher wattage, you may need to reduce the cooking time slightly to prevent overcooking the brownie. Conversely, if your microwave has a lower wattage, you may need to increase the cooking time.
Mixing Texture: When whisking in the sugar, flour, and egg, aim for a smooth and well-combined batter. Be sure to mix thoroughly to avoid any pockets of dry ingredients in the batter, which can affect the texture of the brownie.
Greasing the Mug: Greasing the mug before pouring in the batter helps prevent the brownie from sticking to the sides, making it easier to remove and enjoy. You can use butter, cooking spray, or a light coating of oil to grease the mug. Alternatively, you can use a microwave-safe mug with a non-stick coating for easier removal.