Line two baking sheets with parchment paper and set aside.
To a medium saucepan, add brown sugar, granulated sugar, cocoa powder, and salt. Whisk together.
1 cup packed dark brown sugar, 1 cup granulated sugar, ¼ cup unsweetened cocoa powder, ½ teaspoon salt
To the dry ingredients, add the milk and butter. Turn the heat to low and bring to boil, stirring constantly, until the butter is completely melted.
½ cup milk, ½ cup unsalted butter
Once the butter is fully melted, increase the heat to medium and bring to a boil, continuing to stir. Boil the mixture for exactly one minute while stirring continuously. After one minute, remove the mixture from the heat and keep stirring.
Working quickly, add in the peanut butter and vanilla and stir until the peanut butter is melted.
¾ cup creamy peanut butter, 1 teaspoon vanilla extract
Add in the oats and stir with a rubber spatula until evenly incorporated.
3 cups quick oats
Using a 1-tablespoon cookie scoop (#60), scoop portions onto the prepared baking sheets. The cookies may spread a little - that’s okay. As they cool, they will harden. Allow the cookies to cool at room temperature until firm, about 30 minutes, before serving. Tip: For a firmer texture, refrigerate cookies for 30 minutes before serving