I can't say why exactly, but I decided to make my own peanut butter cups. This is my 'made up as I went along, but rather sucessful' recipe.
Ingredients: A bar of chocolate, peanut butter (if you're cool you'll use crunchy). You'll also need some of those tiny little muffin cases.
Melt a few squares of chocolate, either in the microwave or put them in a bowl on top of another bowl with boiling water in it.
Spoon the chocolate in the cases by putting lots of chocolate on the back of a teaspoon and smooshing it around the case. Lots will drip down to the bottom of the case, but that it good.
Put the cases on a plate in the fridge for 10 minutes to set a little.
Melt up some more chocolate and coat the edges of the cases the same way as before. Once the sides have a good coating put them back in the fridge for 10 to 20 minutes. Eating the excess chocolate is encouraged.
Once they're fairly set spoon a teaspoon of your peanut butter of choice in the case and smooth it down.
Melt a few more squares of chocolate and spoon it over the top of the peanut butter.
You can eat them now whilst the top's all melty and yummy or you can wait till they set and eat them like real peanut butter cups. If you've made the sides thick enough you can even peal off the case before eating them.