NOTE: EQUAL PORTIONS -- You can purchase the large bags of morsels/chips or the small bags. Just make sure they are the same size. I just eye-ball the jar of peanut butter (either chunky or smooth, your choice), getting one that is a similar volume as one bag of morsels that I've purchased. I buy one individual package of holly candy cups at the grocery store and it always has been enough for about two batches.
After you have lined the 2 cookie sheets with aluminum foil (easy clean up) and spread out enough paper candy liners to fill the cookie sheet set them aside.
I have never owned a double boiler so I simply dump the butterscotch morsels in a 1 qt sauce pan and place on low heat to melt. Be careful. They melt quickly so you must stir constantly and watch that you do not do more than simply MELT them.
As soon as you see the last chip disappear into the liquid in the pan, remove from heat and put in an equal portion of peanut butter and stir to incorporate.
Quickly start dropping dollops into the candy cups, filling about 2/3 full. (If you give a small vertical "shake" to the spoon as you drop them in, they will spread out over the entire paper candy cup and flatten out.)
Use the same process as described above to melt the chocolate and then cover each candy cup with the chocolate to both cover and seal the bottom peanut butter layer. Do not do the "shake" with the chocolate if you like the little soft peak it forms. I think it makes them pretty.
When finished let them sit at room temperature until they firm up. This does not take much time. By the time you have the pans washed and the kitchen cleaned up you will be able to test your handy work.
Store in airtight containers with layers of waxed paper between. They do not need to be refrigerated and will last at least two weeks -- or until they are gone -- which is what usually happens to them. They are, of course, better if eaten when freshly made, but they are still very good even after some time has passed so you can make them a few days before you need them and have them ready.
NOTE: I don't bother with putting chocolate in the bottom of the cups. I never saw the need to add a third step that is not really necessary. This recipe will not fall apart when it comes out of the paper cup.