Start with a microwave-safe mug that holds at least 12 ounces. This ensures the batter won’t overflow as it cooks. Gather your ingredients and measure them precisely for the best results.

In your mug, mix the flour, sugar, baking powder, and cocoa powder. Use a spoon to stir until the ingredients are evenly blended.

Pour in the milk, vegetable oil, and vanilla extract. Stir until the mixture becomes a smooth, lump-free batter. Take your time to scrape the sides and bottom of the mug to ensure everything is well combined.

Gently fold in the crushed Oreos. For a chunkier texture, reserve some pieces to sprinkle on top after microwaving.

Place your mug in the microwave and heat on high for 1–1.5 minutes. Every microwave is different, so start with 60 seconds and check for doneness. A toothpick inserted into the center should come out clean or with a few moist crumbs.

Remove the mug from the microwave and let it cool for about 1–2 minutes. Serve as is, or elevate your dessert with whipped cream, a scoop of ice cream, or a drizzle of chocolate syrup.