Preparation Steps

• Preheat oven to 400°F (204°C). Line two baking sheets with parchment paper.
• Using a stand mixer with the paddle attachment, combine cold butter, brown sugar, and granulated sugar. Beat on medium speed until creamy.
• Add the egg and egg yolk and mix until combined.
• Add the vanilla extract and continue mixing until combined.
• In a medium bowl, whisk together flour, cocoa powder, salt, baking powder, and baking soda.
• With the mixer on low, gradually add the flour mixture to the wet ingredients. Mix until mostly incorporated.
• Add the chocolate chunks, chocolate chips, and peanut butter chips. Mix just until the flour is fully incorporated.
• Shape the dough into 8 large balls and place 4 on each prepared baking sheet, spacing them evenly. Gently flatten each ball.
• Bake for 12-13 minutes, or until edges are set. The centers will look slightly underbaked.
• Let the cookies cool on the baking sheet for 10 minutes. Then, transfer to a wire rack to cool completely.