In a medium saucepan, add the chocolate chips, butterscotch chips, peanut butter, and butter. I recommend that you cube the butter into ½ inch cubes as the butter will take longer to melt than the other ingredients. Cook over medium heat, stirring constantly, until everything melts and comes together.
1 c semi-sweet chocolate chips, 1 c butterscotch chips, ¾ c peanut butter, ¼ c butter