Scald 1/2 cup milk. Add 30 regular size marshmallows and mix until melted. Cool and fold in 1 cup cream, whipped. Add 1 large chocolate bar (Hersheys), grated or small size chocolate chips. Add 1 teaspoon vanilla. Line bottom of 9 x 13 inch pan with graham cracker crumbs. Add filling and sprinkle top with crumbs. Chill several hours or overnight.