Combine white chocolate chips and milk in an oversized microwave-safe mug. Microwave for about 40 seconds. Mix with a small whisk or fork until chocolate is completely melted.

Add flour, baking powder, and oil and mix until batter is smooth.

Smash Oreos and mix into the batter.

Cook in microwave for about 1 minute. Let cake cool a few minutes before eating.

Eat warm.