• Place the Oreos in a sealed bag and tap with a rolling pin to form a powder thin as flour.
• In a microwave-safe coffee mug (minimum size 1 cup/250ml), whisk together the Oreo powder, cocoa powder, baking powder, and flour.
• Whisk in almond milk and vanilla extract until a batter forms and stir the vegan dark chocolate chips if desired, or keep the batter plain.
• Microwave on high power (900W) for about 90 seconds, or stop the microwave every 10 seconds until you see the cake rising to its maximum height. Remove from the microwave carefully. It is hot, and check the texture. It should be moist and soft, and the top should deflate. If it is not cooked to your liking after that time, return to the microwave and cook again in 10-second bursts until done - no more than 90 seconds in total. Note that the longer you microwave the mug cake, the denser it will be.
• Serve the Oreo Mug Cake immediately.

Baking option

• Preheat the oven to 350°F (180°C).
• Grease an oven-proof ramekin with oil, add the cake batter and bake for 12-18 minutes until cooked through.
• Serve immediately with toppings of your choice.