Heat oven to 350°F. Grease and flour two 9-inch round pans or one 13x9x2-inch baking pan.
Stir together sugar, flour, cocoa, baking powder, baking soda and salt in large bowl. Add eggs, milk, oil and vanilla; beat on medium speed of electric mixer 2 minutes. Stir in boiling water (batter will be thin). Pour batter into prepared pans.
Bake 30 to 35 minutes for round pans, 35 to 40 minutes for rectangular pan or until wooden pick inserted in center comes out clean. Cool 10 minutes; remove from pans to wire racks. Cool completely.
Prepare the cake balls.
Crumble cooled cake with your hands in a large bowl. Stir in one can of frosting. Stir chopped candy bar into cake and frosting mixture, until well combined. Roll into one inch balls.
Melt chocolate candy melts. Using a toothpick, dip each cake ball into melted chocolate. Set on cookie sheet lined with parchment paper. Allow to set a few minutes until cooled.
Melt white chocolate candy melts and using a small spoon drizzle over cake balls.
Enjoy!