To a mug, add white chocolate chips and milk, and microwave it for 3 minutes to melt the chocolate slightly. Whisk until smooth.
Crush the Oreos. Keep 1 tablespoon of crushed Oreos for garnish. Mix the rest of the Oreos with milk and white chocolate mixture. Add baking powder and mix until smooth.
Microwave on high for 3 minutes.
Remove the mug from microwave and garnish it with whipped cream and remaining crushed Oreos.