Start by making the raspberry sauce. In a medium saucepan on medium-high heat, add in all the ingredients, except the arrowroot powder. Cook for about 3 minutes until the berries soften. Now whisk in the arrowroot powder until it thickens. Pour the sauce into a blender and blend till smooth and creamy.
Make the batter by simply adding all the ingredients into a mixing bowl - mix well. Pour the batter into a large drinking mug but leave 1/4 room at the top for the batter to puff up. Microwave for 60-70 seconds. Top with a dollop of the raspberry sauce and enjoy!