Mix peanut butter and butter until smooth. Add sugar, eggs and vanilla, beat until creamy. Blend in flour and salt, stir in 1 cup of the chocolate chips. spread into ungreased 9x13 pan. bake 25 to 30 minutes at 350 degrees, or until edges begin to brown.remove for oven. Immediately sprinkle remaining chocolate chips over bars. Let stand 5 minutes until chips become shiny and soft. spread over bars. cool.