Preheat the oven to 180°C/350°F degrees. Grease a 6x8-inch pan, or line with parchment.
In a high speed blender, blend all ingredients until smooth. Spread the batter evenly into the pan.
Bake for 20 minutes minutes. Let cool for at least 30 minutes before serving. Serve with frosting or a scoop of your favorite ice cream.