Preheat the oven to 325 degrees F. Spray a 13-by-18-inch sheet pan with cooking spray. Line with a piece of parchment, leaving a 2-inch overhang on each of the short sides.
Make the chocolate-peanut butter cookie: Mix 1 tube of the sugar cookie dough with the powdered peanut butter and 2 tablespoons of the cocoa powder in a medium bowl until completely combined. Fold in 1 cup of the chocolate-peanut butter candies, reserving the rest for topping.
Arrange the sheet pan with a long side facing you. Visualize the pan divided into 4 equal vertical strips. Press the chocolate-peanut butter cookie dough down the far left stripe. Sprinkle with the sanding sugar.
Make the snickerdoodle cookie: Mix the remaining tube of sugar cookie dough with 1/4 teaspoon of the cinnamon in a medium bowl until completely combined.
Press the snickerdoodle cookie dough in a stripe down the section next to the chocolate-peanut butter cookie dough. Mix the granulated sugar with the remaining 1/4 teaspoon cinnamon and sprinkle it over the snickerdoodle cookie dough.
Make the chocolate-chocolate chip cookie: Mix 1 tube of the chocolate chip cookie dough with the remaining 2 tablespoons cocoa powder in a medium bowl until well combined. Fold in 1/4 cup of the candy-coated chocolates.
Press the chocolate-chocolate chip cookie dough in a stripe down the section next to the snickerdoodle cookie dough. Top with the remaining 1/4 cup candy-coated chocolates.
Make the chocolate chip cookie: Press the remaining tube of chocolate chip cookie dough down the remaining quarter of the sheet pan. Press the milk chocolate toffee and cookie crunch squares into the dough, making 5 rows of 2.
Bake the cookie until golden brown and a toothpick inserted into the center of each type of cookie comes out clean, 25 to 30 minutes. Let cool on a rack for 5 minutes.
While the cookie is still warm, top the chocolate-peanut butter cookie with the remaining chopped chocolate-peanut butter candies. Press the snickerdoodle white chocolate truffle halves all over the snickerdoodle cookie. Top the chocolate-chocolate chip cookie with the marshmallows and sprinkle the chocolate chip cookie with the snowflake sprinkles. Allow to cool completely in the pan, about 1 hour.
Use the parchment overhangs to lift the cookie from the pan, then cut into squares.
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