1. Heat oven to 350 degrees F.
2. In a small bowl, combine the graham cracker crumbs, sugar, salt and melted butter until evenly moistened. Transfer the crumb mixture to a 13 x 9 x 2-inch baking pan; press crumb mixture evenly over the bottom and up sides of pan. Refrigerate until chilled and set.Brownie:
3. Combine the bittersweet chocolate and butter in a microwave-safe glass bowl. Microwave chocolate mixture 1 minute. Stir the chocolate mixture until smooth. If necessary, microwave another 15 seconds to melt.
4. In a large bowl, beat together the eggs and sugar on medium-high speed until well blended. Reduce the speed to medium and gradually add the melted chocolate mixture; beat until smooth.
5. Stir the flour and salt into the egg mixture; stir in vanilla until smooth. Scrape the brownie mixture into the crust-lined baking pan; smooth the top level.
6. Bake at 350 degrees F for 30 minutes or until toothpick inserted in center tests clean.Topping:
7. Meanwhile, whisk together the marshmallow cream and the milk until well blended and smooth.
8. Pour the marshmallow topping mixture over the brownie layer. Tilt the pan to level the topping or spread it, covering the brownie layer completely.
9. Sprinkle the mini chocolate Kisses evenly over the marshmallow topping, then scatter the broken graham crackers over the top. Bake at 350 degrees F for 3 minutes or until the chocolate Kisses are glossy and the marshmallow topping is set. Let cool completely in the pan on a wire rack. Cut into 24 bars.