In a large saucepan over low heat, melt the butter, stirring continuously to ensure it doesn't brown. This process should take about 2-3 minutes.

Stir in the mini marshmallows, mixing well until they begin to melt into the butter. Continue stirring for an additional 3-4 minutes until completely melted and bubbly.

Remove from heat and add a few drops of green food coloring. Stir vigorously until color is evenly distributed.

Gently fold in the Rice Krispies cereal using a spatula until all cereal is evenly coated.

Line a cookie sheet with wax paper and pour the mixture onto it, spreading it out evenly to about an inch thick. Let it cool for about 5-10 minutes.

Use a heart-shaped cookie cutter to cut out heart shapes from the cooled mixture and transfer them to clean wax paper.

Gently press a small red candy into the center of each heart and allow the treats to set for a few minutes before serving.