Heat the heavy cream in a saucepan over medium heat, until bubbles start to form on the side, about 2 minutes. remove from heat.
Add the chocolate to the pan. Let it sit for a minute or two, then whisk until smooth; set aside to cool.
In a food processor, pulse the graham crackers into fine crumbs. Add the melted butter, pulse a few times until the mixture resembles wet sand; set aside.
To assemble: Spoon a 1/4 of the graham cracker mixture to the bottom of the mason jars. Then add 1/4 of the marshmallow cream (I piped this in), 1/4 of the chocolate ganache, then top with mini marshmallows.
Using a cooking torch, toast the marshmallows until browned and serve!