Lightly grease a large baking sheet with cooking spray.
Cooking spray
In a large saucepan, melt the butter over low heat.
3 tablespoons butter
Add the marshmallows and stir continuously until completely melted. Remove from heat.
10 oz marshmallows
Stir in the vanilla extract and food coloring (if using).
1 teaspoon vanilla extract, Pink or red food coloring
Gradually add the Rice Krispies cereal to the melted marshmallow mixture, stirring until evenly coated.
6 cups Rice Krispies cereal
Transfer the mixture to the prepared baking sheet. Gently press the mixture down using a spatula or your hands (greased or covered with parchment paper to prevent sticking) until it's about 1 inch thick.
While the mixture is still slightly warm, use a heart-shaped cookie cutter to cut out hearts.
Immediately decorate the hearts with Valentine's Day sprinkles while they are still sticky.
Valentine's Day sprinkles
Let the Rice Krispie Valentine Hearts cool completely on the baking sheet before serving or packaging. Enjoy!
