Thin Mint Cookie Sheet

This is a giant thin mint cookie. Making thin mints requires cutting perfect circles out of cookie dough, wasting dough, melting chocolate, and wasting chocolate. This version is less laborious and wasteful. No cutting, melting, or dipping. All the dough is baked in a giant sheet, and all the chocolate is melted on top from the heat of the cooling cookie.

You can make this into any size or shape; If you want to make 3 frisbee-size cookies, go ahead. I baked mine for 25 minutes and got a very crispy cookie, so if you want something softer, shorten baking time to 20 minutes.

Thin Mint Cookie Sheet Recipe Success Guide:

The most challenging part is evenly rolling out the dough into a rectangle. Use plenty of cocoa powder to prevent the rolling pin from sticking.

If your cookie sheet too small to fit the entire sheet (smaller than a half-sheet pan), divide the dough into two batches and reduce baking time by a few minutes.

Estimated Baking Times for Crispy Cookies:

reduce by ~4 minutes for chewier cookies

Traditional small thin mint sizes: 15 minutes
Giant sheet: 25 minutes
Giant sheet in two batches: 22 minutes
Frisbee-sized cookies: 20 minutes

Ingredients

Necessary Kitchen Stuff:
Parchment Paper
Large cookie sheet

Cookie:
1 cup sugar (205g), granulated or brown or a mix of both
12 tbs (1.5 sticks) butter, room temperature
1/2 tsp salt
1 egg
1.5 tsp peppermint extract
1.5 cups (190g) all-purpose flour
1 tsp baking powder
3/4 cup (63g) cocoa powder

Chocolate Coating:
4 candy canes/ ~6 peppermints, crushed
1 (10 oz) bag bittersweet chocolate chips

Step-by-step Instructions

Preheat oven to 350F/180C
In a large bowl, cream together room temperature butter and sugar with an electric beater until light and fluffy, about 3 minutes
Add egg, salt, and peppermint extract and beat until combined, 20 seconds.
Sift in flour, baking powder, and cocoa powder. If you don’t have a mesh strainer for sifting, you can whisk the dry ingredients together in a separate bowl, breaking up clumps of cocoa powder with your fingers before adding.
Beat dry ingredients into butter mixture until incorporated, about 30 seconds. Form the dough into a ball, and transfer to a cutting board lined with a large sheet of parchment paper.
Flatten the ball into a disk shape. Dust the top with more cocoa powder, and roll it into a large rectangle 1/4 inch (.5cm) thick. I like to press another sheet of parchment on top while rolling, but you can also just keep dusting with cocoa powder to prevent sticking. Ideally, the cookie should be the length and width of your baking sheet.
Slide the parchment directly onto the cookie sheet, and bake for 20-25 minutes. (20 for softer cookies, 25 for crispier)
Meanwhile, crush your candy canes or peppermints in a bag with a rolling pin.
Remove cookie from oven, and immediately spread chocolate chips over the top in an even layer. Let sit for 5 minutes, or until chips are melted. Spread melted chocolate evenly with an offset spatula/ back of a spoon.
Sprinkle crushed peppermint over the top.
After it’s completely cooled, break into pieces.