Once butter is melted, add vanilla and 6 cups of marshmallows. Melt the marshmallows slowly.
Right before the marshmallows are fully melted, add milk and the other 2 cups of marshmallows. Stir until the added marshmallows are starting to melt. (we don't want them fully melt so you will have a lumpy fluff)
Add the food coloring. Adjust amount to your taste.
Add the Rice Krispie Cereal. Stir until the cereal is fully coated with the marshmallow fluff.
Dump into an 9 x 13 greased dish. Use a greased spatula to spread out the treats and press down.
Allow to fully cool before cutting.
Melt the red candy melts in a disposable bag in the microwave according to instructions.
Pipe hearts onto each treat.
Once the candy melts have harden, serve.
Notes
The number of treats will depend on how you cut your treats.Make sure to read the post for a few tips.