In a microwave-safe mug, add 4 tablespoons of all-purpose flour, 1/4 teaspoon of baking powder, and a pinch of salt. Mix thoroughly until evenly combined.

Pour in 3 tablespoons of milk and 1 tablespoon of olive oil (or melted butter) into the dry mixture. Stir until the ingredients meld into a smooth batter.

Place the mug in the microwave and cook on high for 1 to 2 minutes. Start checking at the 1-minute mark and cook until firm to the touch.

Carefully remove the mug from the microwave and let it cool for about 1 minute. Once cool enough to handle, release the bread and slice it.