As part of an effort to simplify my life (and fit all my food into one cabinet) I do not buy cookies or other desserts. Instead, I buy chocolate chips, which I typically find to be higher quality than candy-bar chocolate anyway. I also stock peanut butter (made from pure peanuts) and whole-wheat bread, and if I feel like a dessert-style snack, I make a sort of peanut-butter and chocolate open-faced sandwich.
Yesterday, the temperature in my apartment rose to the point that my bag of 53% cacao Nestle Chocolatier chips melted to the consistency of Nutella. Today, they are a solid block of chocolate. Thus, I have been reduced to eating straight chocolate out of the bag, with a fork.
YUM! But seriously, you can crack off a piece, put it into a small microwavable bowl for a few seconds and make a liquid out of it. If too thick add a few drops of milk, and spread it on your bread and then add the peanut butter. The chocolate will get hard very quickly, so it is better to spread it first.