Preheat oven to 350.
In large mixing bowl beat peanut butter and butter until smooth.
Add sugar, eggs, and vanilla. Beat until creamy.
Blend in flour and salt.
Stir in 1 cup of milk chocolate chips.
Spread in ungreased 13 x 9 inch baking pan.
Bake 25 minutes or until edges begin to brown.
Immediately sprinkle with remaining chocolate chips.
Let stand 5 minutes until morsels become shiny and soft.
Spread evenly over top. Cool completely