In a large pot on the stove add the butter and apply medium heat to melt.

Once the butter has completely melted add the vanilla and salt and stir well.

Add the marshmallows and stir continuously, until no shapes remain in the mixture. Takes about 5 minutes.

Add the Rice Krispies and stir well to coat all the Rice Krispies evenly.

Empty out onto a cookie sheet lined with wax paper, or parchment paper that has been sprayed with kitchen spray.

Smooth out using a spoon greased with cooking spray. Once cooled enough you could spray your hands and use your hands too.

Smooth out until about ½" thick, then use a heart shaped cookie cutter (greased) and cut out heart shapes from the Rice Krispie mixture. Cut different sizes (like I did) if you want.

Once the heart shaped rice krispie treats have cooled completely you can decorate with the frosting and sprinkles however you like. I like to decant the frosting into a piping bag to be able to pipe out pretty patterns. You can just spoon it on there too if you like.

Wait a few hours to harden enough to eat.