Into a 12-ounce microwave-safe mug, add the flower, sugar, cocoa powder, baking powder, and salt. Stir with a fork. Add the milk, vegetable oil, and vanilla and stir until smooth. Stir in the chocolate chips. Use a damp paper towel to wipe excess off the sides of the mug.
Microwave for 90 seconds, then let the cake stand for 1 1/2 to 2 minutes before eating. Serve with sweetened whipped cream or vanilla ice cream!