Line two greased 9-inch round baking pans with waxed paper and grease the paper; set aside. In a large bowl, combine the cake mix, coffee and egg whites; beat on low speed for 30 seconds. Beat on medium for 2 minutes. Fold in chopped candy bars.
Pour into prepared pans. Bake at 350 degrees for 25–30 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing to wire racks to cool completely.
For frosting, in a large bowl, beat cream cheese and sugar until smooth. Beat in chocolate syrup and vanilla. Add the whipping cream. Beat on high speed until light and fluffy, about 5 minutes.
Cut each cake horizontally into two layers. Place bottom layer on a serving plate; drizzle with 2 tablespoons of the coffee. Spread with ¾ cup frosting. Repeat layers twice. Top with the remaining cake layer. Frost top and sides of cake with remaining frosting. Refrigerate overnight. Garnish with chopped candy bar.