For the pastry flour, I used Bob's Red Mill which comes in a big pink bag. You could swap out the pastry flour for an even mix (160 grams each) of bread flour and cake flour or possibly use King Arthur AP. I really am enjoying the Bob's flour. For the chocolate, I like Lindt Sweet Dark which melts quite nicely. It doesn't set up very quickly, so I like to set the chunks by throwing the cookies in the freezer. Then again, I'm a weirdo who doesn't like these gooey or melt-y.