Add the graham crackers to a zip up baggie and seal. Use a meat mallet or pan to turn the graham crackers into crumbs.
Divide the graham cracker crumbs evenly into four dessert cups.
In a medium bowl, whisk together the Greek yogurt, vanilla pudding mix, and marshmallow extract until smooth and thickened.
Spoon or pipe the filling evenly over the graham cracker layer.
Melt the Hershey's Zero Sugar chocolate bars in the microwave in 20-second intervals at 50% power, stirring after each until smooth.
Drizzle the melted chocolate over each dessert cup.
Optional: Garnish with graham cracker crumbs.