In a mixing bowl combine the butter, peanut butter, brown sugar, corn syrup and vanilla; gradually stir in the oats. Press into a greased 9x13 inch pan. Bake at 400 degrees F for 12-14 minutes or until edges are golden brown. Cool.
Topping Ingredients
1 cup milk chocolate chips
1/2 cup butterscotch chips
1/3 cup peanut butter
Meanwhile, for topping melt chips and peanut butter in a saucepan over low heat. Stir until blended; spread over warm bars. Cool completely, and refrigerate for 2-3 hours before cutting.