Preheat broiler to 500F. Line a baking tray with tin foil.
Break graham cracker sheets into squares and place onto baking tray, spaced one inch apart.
Break chocolate bar into squares and place on top of graham cracker squares. Top each square with a heart marshmallow.
Place tray in oven under broiler for roughly 60 to 90 seconds. Watch the whole time so that the marshmallows do not burn. Just lightly toast!
Remove from oven and add sprinkles before chocolate sets, if using. Let cool. Use a spatula to move s’mores to a serving plate.
I used classic Hershey chocolate bars.
If you want to eat these right away, I recommend topping with another graham cracker (after you show them off!) to help contain the ooey, gooey, goodness! Or you can prepare these 30 minutes to several hours in advance. This allows the chocolate to firm up so you can enjoy them open faced, heart exposed!
To make a day in advance, allow cookies to completely cool so that the chocolate is firm. Store in an air tight container until ready to use.
Once set, these store nicely in individual clear bags tied with ribbon.