Grab a microwave-safe mug (10-12oz capacity).
Add the milk and Oreos, then use a fork to crush the Oreos until the mixture looks like a paste.
Toss in the oil, vanilla, and sugar. Stir with the same fork until it's all combined.
Now, sift in the dry ingredients: flour, cocoa powder, baking powder, and salt. Gently mix with the fork until just combined – no overmixing!
Microwave on high for 60-90 seconds (around 85s for me) until the cake is fully cooked.
While it's still warm, sprinkle chocolate chips on top so they melt from the cake's heat. Spread the chocolate and finish with crushed Oreos.
Serve it up and savor the deliciousness!