This is an excellent cookie book and every cookie I've made from it has been outstanding. Unfortunately, there's one recipe that temps me over and over again -- even though I've failed at it everytime. It's a divine-looking recipe for a chocolate- and almond-topped toffee called Mahogany Buttercrunch. It looks so-o-o tempting. Unfortunately, I am a novice at candymaking and every attempt to prepare this recipe has been an ignominious failure. I even went out and bought a professional candy thermometer -- didn't help.
The instructions are pretty skimpy and don't tell you anything about how (or if) it's possible to rescue the toffee if the sugar crystalizes or the butter separates out (both have happened to me). I've tried to supplement my knowledge by going to candymaking sites on the internet, but they're full of conflicting advice. I should avoid hot days, damp days; I should use a wooden spoon to stir the mixture; I should raise the temperature under the pot and stir continuously; I should lower the temperature and stir as little as possible. If the butter separates, try dumping in a half cup of very hot water; no -- add a little bit of hot water a tablespoon at a time; no -- do nothing but keep cooking and stirring, it might go back in by itself.
My advice is to buy the book and make the cookies. However, unless you have candymaking experience, don't attempt the Buttercrunch!