Preheat oven to 375 degrees. Grease a 9 x 13 in pan.
Combine flour, baking soda and salt in small bow. Beat butter, sugar, brown sugar and vanilla in a large mixing bowl until creamy. Add eggs, one at a time, beating well after each addition. Gradually mix in flour mixture. Stir in chocolate chips.
Spread half of cookie dough into the prepared pan. Bake for 8-10 minutes. Remove from oven.
While the cookie dough is baking melt caramels and evaporated milk in a double boiler. Add peanut butter after caramels are melted. Melt thoroughly. Spread over baked cookie dough base.
With the remaining cookie dough, drop by spoonfuls ontop of the caramel mixture.
Bake for 15-20 minutes or until light golden brown.
