3/4 cup all-purpose flour
1/4 cup unsweetened cocoa powder, regular or extra dark
1 stick, (1/2 cup) unsalted butter, room temperature
1 Tbsp vanilla extract
heaping 1/2 cup walnuts, rough chopped
Whisk together the dry ingredients. You can use a wooden spoon or a stand mixer. Add in the butter and the vanilla, and stir until completely mixed and a soft dough forms. Fold in the walnuts and turn the dough onto a piece of parchment paper. Form the soft dough into a rough log, about 7-8 inches long. Roll up in the paper, smoothing the log and twisting the ends firmly to form a secure package. Refrigerate for 2 hours, or freeze for 1 hour if you're in a hurry, then unwrap and slice into thin slices, about 1/4-1/3 inch. Preheat oven to 325F. Place on a silpat or parchment lined baking sheet and bake for about 10 to 12 minutes. Just until set. Cool for a minute on the tray, then transfer to a cooling rack.