Grab a microwave-safe mug. Choose an 8 to 12-ounce mug to give the cake room to rise. Lightly grease the inside if you want an extra-soft edge.

Mix dry ingredients in the mug. Add the self-rising flour and sugar. Stir with a fork until well combined and no clumps remain.

Add the milk. Pour in the milk and mix until you have a smooth, thick batter. Scrape the bottom and sides so everything is incorporated.

Customize if you like. Fold in chocolate chips or swirl in a teaspoon of peanut butter. A splash of vanilla adds a bakery-style touch.

Microwave. Cook on high for 60 to 90 seconds. Start checking at 60 seconds—tops will look set but slightly glossy. If it’s wet in the center, microwave in 10-second bursts.

Rest before eating. Let the mug cake sit for 1 minute. It finishes cooking with residual heat and becomes extra tender.

Top and enjoy. Serve as is, or add a scoop of ice cream, a drizzle of chocolate sauce, or a dusting of cinnamon.