In a blender, mix together crepe ingredients. Cover and chill in refrigerator at least an hour. Overnight is best.
Heat a medium nonstick pan over medium/high heat, and brush lightly with butter or cooking spray.
Drop 1/4 cup of mixture onto the heated pan, immediately picking up the pan and tilting it in a circular motion, making a thin crepe.
Cook for 1-2 minutes on the first side, flip it, and 30 seconds on the other side.
Stack crepes to the side on a plate (depending on the size of your pan, it should make between 8-12 crepes).
In a medium bowl, beat the heavy cream until it turns frothy. Add the powdered sugar, vanilla, and cake mix gradually while beating. Whip until light and has a thick enough consistency to spread as an icing.
Spread icing evenly between each crepe, and use any remaining icing on top. Top with sprinkles and let it cool in the refrigerator 1-2 hours before serving.