1Combine oil, milk, egg yolk, sugar and vanilla in a small bowl. Add flour and baking powder and stir to combine. Gently fold in blueberries. Spoon batter into an 8-ounce ceramic mug and place mug on turntable.
2Press MICROWAVE, set 100% power for 1 minute 30 seconds and press START to begin cooking.
3Make Cream Cheese Icing: Combine cream cheese and powdered sugar in a small bowl and stir to combine.
4Remove cake from microwave and let cool slightly. Serve cake warm, topped with Cream Cheese Icing.