Slowly melt the butter in a large pan, low heat.

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 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 just a bit (you don't want them to so compacted that they become rock hard).

Allow the treats to fully cool and set up.

Using a heart shaped cookie cutter, cut out heart shaped treats and set aside.

Sprinkle a flat surface with powdered sugar.

After kneading the fondant, roll it out thinly on the powdered sugar surface.

Using the same cookie cutter, cut out a hear shape.

Spread a thin layer on top of the rice krispie treat.

Lay the fondant heart over the rice krispie treat and press down gently to put it in place.

Allow to harden a bit before writing on the hearts with the food writer. (I used a red one).