In a mixing bowl, combine the sugar, flour, cocoa powder, eggs, melted butter, and salt. Mix until just combined. Pour into a greased 9x13 baking pan. Bake in a preheated oven, 350, for about 30 minutes. Allow brownies to cool completely. Meanwhile, combine the peanut butter, powdered sugar, butter, and milk in a bowl. Once brownies are cooled, spread the frosting on to the brownies to desired thickness. Sprinkle Reese's pieces on top of frosting. Drizzle the melted chocolate chips on top of the Reese's Pieces. Cut into desired size pieces and enjoy! Store in an airtight container!