In an 8 ounce mug, use a fork to mix together the flour, sugar, baking powder and salt until well-combined.
Add the milk, vegetable oil, vanilla (or cocoa) and half of the sprinkles. Stir until fully mixed, being sure to scrape the bottom of the mug.
Top with the remaining sprinkles.
Cook in the microwave for 1 minute and 30 seconds or until the top is opaque and the cake is cooked through.
Serve with whipped cream and extra sprinkles.
Notes
Use a tall mug: Give the batter room to rise without spilling. Measure lightly: Spoon and level flour so the cake stays soft. Mix to the corners: Scrape the mug so there are no dry pockets. Check doneness: Stop cooking as soon as the top sets, to avoid a rubbery texture. Serve warm: The crumb tastes best when it’s just cooked.