Line a cookie sheet with some parchment paper and set it aside. Make sure your mold is washed, dried and cut into individual hearts for easy molding.
Chop your chocolate finely and then place into the microwave for 30 seconds. Stir.
Continue heating for 15-second increments and stirring. Check the temperature every time to make sure you do not go above 88ºF. If you do go above 88ºF then you can temper the chocolate using the seeding method. See the blog post for more details.
Once your chocolate is melted you can divide it into three batches. I colored one batch with a few drops of pink cocoa butter, one batch with some crushed freeze-dried strawberries and one I left white.
Heat your melted chocolate up to 88ºF again (I re-heat in 5-second increments only).
Pour the chocolate into the heart mold and let it cool for a few moments to build up the shell.
Pour the excess chocolate out of the mold and give it a shake to make sure as much is out as possible.
Place the mold upside down onto the parchment paper. Once all the molds are done, place the tray into the freezer for 5 minutes.
Carefully remove the chocolate shells from the mold.
Heat a plate up in the microwave for 1 minute. Place the front and back of one mold onto the plate for 5 seconds to melt the edges and flatten them out. Then remove them from the plate.
Fill one half of the mold with 1 Tablespoon of cocoa mix. Add 2 drops of strawberry oil for more flavor and as many marshmallows as you can fit in there.
Add the top of the mold onto the back and press together with gloved hands to seal.
Drizzle more melted chocolate on top of the hearts and add sprinkles, crushed dried strawberries, or any decorations you want.