Preheat oven to 375 degrees F. Spray muffin tin generously with cooking spray.
Melt the butter in a small bowl and add the vanilla; mix well and set aside.
In another small bowl, combine the cake mix and brown sugar.
Cut each biscuit and cut into four pieces.
Working four pieces at a time, dip four pieces in the butter/vanilla mixture, coating completely. Using a fork, remove from the butter mixture and coat thoroughly in the cake mix mixture. Place four coated pieces into each muffin tin. Repeat until all eight tins are full.
Bake for approximately 12-15 minutes or until lightly golden and centers appear set. *Do not overbake* Allow to cool in pan for about 5 minutes before gently removing them with a butter knife (just run the knife along the edge of the cavity to gently pop them out).
Place a dollop of frosting on the tops of the still-warm muffins and top with sprinkles.
These are best served warm, but can be reheated in the microwave for about 10-20 seconds and served within one day.