10 tablespoons (140 grams) unsalted butter1 1/4 cups (250 grams) may vary by brands) unsweetened cocoa powder (natural or dutch-process)1/4 teaspoon salt (or a heaping 1/4 teaspoon flaky salt, as i used)1/2 teaspoon pure vanilla extract2 large eggs, cold1/2 cup (65 grams) all-purpose flour2/3 cup (75 grams) walnut or pe