I love this Thin mints chocolate covered its yum, I made it last Friday. Its so yummy when you eat it the day after you bake it, husband didn't like it that much when its freshly bake but after a day he said it taste good and asked for more lol, bad husband.
Recipe from Ms Lyn's sweet memories desserts blog

2 1/4 cups all purpose flour
1/4 cup cornstarch
6 tbsp unsweetened cocoa powder
1/2 tsp salt
1 cup white sugar
1/2 cup butter, room temperature
1/3 cup milk (any kind)
1/2 tsp vanilla extract
3/4 tsp peppermint extract

In a small bowl, whisk together flour, cornstarch, cocoa powder and salt.
In a large bowl, cream together butter and sugar. With the mixer on low speed, add in the milk and the extracts. Mixture will look curdled. Gradually, add in the flour mixture until fully incorporated.
Shape dough into two logs, about 1 1/2 inches (or about 4 cm) in diameter, wrap in plastic wrap and freeze for at least 1-2 hours, until dough is very firm.
Preheat oven to 375F.
Slice dough into rounds not more than 1/4 inch thick - if they are too thick, they will not be as crisp - and place on a parchment lined baking sheet. Cookies will not spread very much, so you can put them quite close together.
Bake for 13-15 minutes, until cookies are firm at the edges. Cool cookies completely on a wire rack before dipping in chocolate.

Dark Chocolate Coating
10-oz dark or semisweet chocolate
1/2 cup butter, room temperature

In a microwave safe bowl, combine chocolate and butter. Melt on high power in the microwave, stirring every 45-60 seconds, until chocolate is smooth. Chocolate should have a consistency somewhere between chocolate syrup and fudge for a thin coating.
Dip each cookie in melted chocolate, turn with a fork to coat, then transfer to a piece of parchment paper or wax paper to set up for at least 30 minutes, or until chocolate is cool and firm.
Reheat chocolate as needed to keep it smooth and easy to dip into.

Makes 3 1/2-4 dozen cookies.