In a separate bowl mix dry ingredients together. Set aside.
In a 1-cup measuring cup mix wet ingredients until thoroughly combined.
Add wet ingredients to dry. Stir until no flour is visible.
Transfer to greased mug. Bake in microwave for 1½ - 2 minutes**. Time will vary based on microwave wattage. (see notes)
Let cake cool for 2 minutes. Garnish as desired and serve.
Notes
**Microwave settings - Find the wattage of your microwave on a label around the door. Adjust cooking time and power level to determine the best settings to bake a mug cake. I bake mine in a 1200 watt microwave at power level 7 for 2 minutes. (It is possible to burn a cake in the microwave. If your microwave is 1200 watts or higher use a setting less than full power.) Batter can be divided into 2 smaller mugs or Mason jars and baked at the same time.Cooked cake can be transferred to 2 mugs or plates if serving 2.Mug Cake Variations:Chocolate Mug Cake - Add 1 tablespoon cocoa powder to the dry mix. Replace 2 teaspoon sprinkles with 2 teaspoon mini chocolate chips.Lemon-Blueberry Mug Cake - Replace 1 tablespoon milk with 1 tablespoon lemon juice. Replace 2 teaspoon sprinkles with 2 teaspoon small blueberries.