Preheat oven to 350 F. Line a 12 cup muffin tin with paper liners. In a small bowl, combine crushed graham crackers with melted butter. Press the mixture evenly into each paper liner.
In a large bowl with a mixer, beat softened cream cheese with granulated sugar until fluffy. Add in eggs and vanilla extract and beat until smooth. Divide the cheesecake batter between each muffin cup.
Bake for 25-30 minutes. Divide each chocolate bar in half and place each half onto the cheesecakes. Place 3 mini marshmallows on each cheesecake and bake for another 3-4 minutes. Let cool completely.
