The Mint Slice is an Australian supermarket staple, a cookie second only to the Tim Tam (which you’ve probably heard about). It’s very similar to a Thin Mint—both have crisp dark chocolate cookie bases and a thin covering of dark chocolate.
The kicker with the Mint Slice, however, is the layer of mint icing nestled between the crispy base and the chocolate coating; that icing is what takes these cookies to a whole new level.
Even though these are definitely a year-round treat in Oz, their holiday appeal is undeniable. They go so perfectly with a cup of tea, coffee, or hot chocolate, and their peppermint scent is completely Christmas-y. Mint Slice cookies have great make-ahead potential, too. Not only can the raw dough be stored in the freezer for up to two months, well wrapped, but the assembled cookies freeze beautifully, too.
These are a little time consuming to put together, but they’re very simple. The cookies are slice and bake, and the mint icing simply stirs together. In fact, if you’re not too worried about potentially getting melted chocolate everywhere, these could be a great project to do with kids.
Not only are these perfect for gift giving, cookie swaps, and even keeping little ones entertained, they're also the perfect solitary treat for every and any moment that you can sneak between the holiday bustle of wrapping presents, shopping, baking, and watching marathons of cheesy movies (which is not to say these wouldn't go really well with The Santa Clause, You’ve Got Mail, and Elf).
Makes 20 cookies
For the cookies:
4 ounces butter, softened
1/2 cup granulated sugar
1/4 cup cocoa powder
1 cup all-purpose flour
For the filling and the coating:
1 1/2 cups powdered sugar
1/2 teaspoon peppermint extract
4 ounces milk chocolate
2 ounces dark chocolate
1 tablespoon coconut or vegetable oil
Cream together the butter and sugar until the mixture is light and fluffy. Scrape down the bowl, add the egg, and continue beating until the egg is incorporated and the mixture lightens in color. Add the cocoa powder to the egg mixture and beat until there are no lumps. Finally, fold in the flour until it is all incorporated. You should expect the dough to be very soft.
Turn it out onto a piece of baking paper, roll it into a log about 1 1/2 inches thick, and wrap the dough. Place the log into the freezer to chill for at least 30 minutes. Preheat the oven to 350° F (180° C) and line two baking sheets with baking paper.
When the dough is finished chilling, take it out of the freezer and slice it into 1/2-inch pieces; you should get about 20 rounds. Place the cookies onto the baking sheets and bake for 10 minutes. Remove the cookies from the oven and leave them to cool completely on the baking sheets.
To make the mint filling, simply stir together the powdered sugar, the peppermint extract, and 1 tablespoon of water. The mixture should be very thick, like the texture of playdough. Take a scant teaspoon of the mint filling and use it to top each cookie, patting and smoothing it with your fingers so that it covers the top but stops shy of the edge of the cookie.
To coat the cookies, melt the chocolates and the coconut (or vegetable) oil together in the microwave in short bursts, stirring well between each until you have a smooth mixture. Once the chocolate mixture has cooled slightly, dip each cookie in the chocolate, coating it completely.
Set the coated cookies on a rack over a piece of foil or parchment paper to drip and set. Once they're set, these should be stored in the fridge, where they'll keep well for at least a week. They also freeze beautifully for up to a month in an airtight container, and they even taste great straight out of the freezer.
Photos by Sarah Coates