In a food processor, combine the flour, cocoa, sugar, salt, and baking soda. Pulse several times to mix thoroughly. Cut the butter into about 12 chunks and add them to the bowl. Pulse several times. Combine the milk and vanilla in a small cup. With the processor running, add the milk mixture and continue to process until the dough clumps around the blade or the sides of the bowl. Transfer the dough to a large bowl or cutting board and knead with your hands a few times to make sure the dough is evenly blended. Portion the dough into equal thirds. If you have a scale, weigh each third; each should weigh about 12 oz. Make the recipes for Bittersweet Mocha Cookies, Chocolate Chunk Cookies with Dried Cherries & Pecans, and Crunchy Cocoa Wafers before chilling the dough.
Photo: Scott Phillips