Using a double boiler, place water in the bottom of the double boiler so the top of the water is 1/2 inch below the upper pan. Then place the double boiler over low heat. Make sure that the water does not ever boil, we want to keep the temperature just below the boiling point.
When preparing this recipe be careful not to allow water (even a drop) to touch the chocolate. This will cause the chocolate to seize.
Stir in the chocolate, butter, and milk, keep stirring until melted.
Once the chocolate has melted add the peanut butter chips to the middle of the chocolate and stir carefully until swirled and peanut butter chip are melted.
If you prefer a smoother texture, then add a 1/4 cup of milk.