Step 1

Position oven racks in the top and bottom thirds of the oven and preheat to 350 degrees F.

Step 2

Whisk together the flour, baking powder, baking soda and salt in a bowl until evenly combined. Combine the butter, brown sugar and granulated sugar in a large bowl and beat with an electric mixer on medium-high speed until light and fluffy, about 3 minutes. Beat in the vanilla, then add the eggs and yolks 1 at a time, beating well after each addition. Add the flour mixture and beat on low until the dough just comes together. Add the chocolate candies, oats, pretzels, peppermint puffs and white chocolate chips and stir with a large spoon until evenly mixed.

Step 3

Scoop eight 1/3-cup portions of dough, roll into balls and divide between 2 baking sheets, spacing the cookies evenly apart. Press the dough balls into thick disks with the palm of your hand. Bake, rotating the baking sheets top to bottom and front to back halfway through, until the cookies are golden brown at the edges and barely brown in the very middle, 18 to 20 minutes. Cool the cookies on the baking sheets for 1 minute, then transfer them to a wire rack to cool completely. Repeat with the remaining dough.