Preheat oven to 350 degrees F. Grease a 9 by 13-inch baking pan.
Cream together 1/2 cup of the peanut butter and butter and then add the sugar and brown sugar and blend together. Mix in the egg and then the vanilla.
Sift together the flour, baking soda, and salt. Add this to the peanut butter mixture and mix until well blended.
Pat the dough into the prepared pan. Place in the preheated oven and bake for 22 to 24 minutes.
Once the crust is baked remove it from the oven and melt the caramel bits. Place the caramel bits in a microwave-safe bowl along with the cream. Microwave until melted stirring about every 30 seconds. Pour the melted caramel over the bars.
Set the bars on a cooling rack and cool completely.
Add the milk chocolate chips, semi-sweet chocolate chips, and the remaining 1/2 cup peanut butter in a microwave-safe bowl and melt together. Mixing every 30 seconds. Blend together and spread over the cooled bars.