Instructions

• Preheat the oven to 350°F when you are ready to bake.
• Line a baking sheet with parchment paper and set aside.
• In a medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt. Set this dry mixture aside.
• In the bowl of a stand mixer (or a large mixing bowl with a hand mixer), beat the softened unsalted butter with the granulated sugar and packed dark brown sugar until light and fluffy, about 2–3 minutes.
• Add the egg, vanilla extract, and freshly grated citrus zest to the butter-sugar mixture and mix just until combined.
• With the mixer on low speed, add the dry flour-cocoa mixture to the wet ingredients and mix until just combined. Do not overmix.
• Using a spatula, fold the old-fashioned oats, Cheerios, and semi-sweet chocolate chips into the dough until evenly distributed.
• Cover the dough and refrigerate until thoroughly chilled, about 2–3 hours or preferably overnight.
• When chilled and ready to bake, use a tablespoon or a tablespoon-sized scoop to portion dough into tablespoon-sized balls. Place the dough balls on the prepared baking sheet, leaving at least 2 inches between them.
• Bake for 9–11 minutes, until the edges are set. The centers may still look slightly soft.
• Let the cookies cool on the baking sheet for 3 minutes, then transfer them to a cooling rack to cool completely.