Step 1

Spray the bottom of a microwave-safe mug or coffee cup  lightly with cooking spray.Add flour, sugar, cocoa powder, baking powder, and salt and stir together.

Step 2

Add milk, canola oil, and vanilla extract and stir until smooth, being sure to scrape the bottom of the mug. Stir in chocolate chips or sprinkle them on top.

Step 3

Cook in microwave for 70-90 seconds (see note) until cake is just set, but still barely shiny on top. (see notes below). Allow to rest in microwave for 1 minute before consuming.