In a large saucepan, melt the butter and marshmallows together over medium-low heat.
Stir in the cake mix.
Use a spatula to fold in the cereal into the melted marshmallow mixture.
Spread into a 9x13 casserole dish and let them set for 20 minutes.
Transfer the crispy treats onto parchment paper.
Use a heart cookie cutter to cut out each one.
In a microwave-safe bowl, melt the candy melts in 30-second intervals until smooth.
Dip the Rice Krispy treats into the melted candy, and add Valentine's day sprinkles immediately.
Allow them to set before storing.