01 - In a microwave-safe mug (at least 12 oz), whisk together the gluten-free flour blend, cocoa powder, sugar, baking powder, and salt until evenly distributed.
02 - Pour in the milk, oil, and vanilla extract. Stir thoroughly until the batter is completely smooth with no lumps remaining.
03 - Gently fold in the chocolate chips if using, distributing them evenly throughout the batter.
04 - Microwave on high power for 1 minute 30 seconds to 2 minutes, until the top is set and springs back lightly when touched. Cooking times may vary depending on your microwave wattage.
05 - Allow the mug cake to rest for 1 to 2 minutes before serving. Top with whipped cream or fresh berries if desired.