Cover a large, flat plate or cookie sheet with waxed paper and set aside.

Slice the butter into 8-10 pieces and add it to a large bowl. Add the Funfetti cake mix, sugar, flour, and vanilla extract.

Using a fork, work the butter into the flour and cake mix until thoroughly combined and resembles smooth cookie dough.

If the dough is too dry, add 1-2 tablespoons of milk or water and mix in the rainbow sprinkles.

Scoop one tablespoon of truffle batter using a cookie scoop or measuring spoon and roll it into a ball using your palms. Place the truffle balls on the prepared baking sheet.

Freeze the truffles for 10 minutes before coating them with white chocolate.

Add white chocolate wafers to a microwave-safe bowl and melt for 30 seconds. Stir well and microwave for another 20 to 30 seconds, stirring well again. If necessary, microwave for another 10-15 seconds until fully melted.

Using a fork, dip each dough ball into the melted white chocolate and place on the prepared plate. Immediately top with sprinkles.

Place truffles in the fridge for at least 20-30 minutes or until the white chocolate coating hardens.

Store truffles in the fridge for up to 7-10 days.