Chocolate Peppermint Cookies

Chocolate peppermint cookies
Makes about 2 dozen cookies.
Note: From finalist Karen Evans of Minneapolis.
For cookies:
• 1 1/2 c. flour
• 1/2 c. unsweetened cocoa powder
• 1/4 tsp. salt
• 1/4 tsp. baking powder
• 1/4 tsp. baking soda
• 1/2 c. (1 stick) unsalted butter, at room temperature
• 1 c. granulated sugar
• 1 egg
• 1 1/2 tsp. vanilla extract
For topping:
• 3 tbsp. butter, at room temperature
• 2 c. powdered sugar
• 1 tsp. peppermint extract
• 1 to 3 tbsp. milk (or heavy cream)
• 1/3 c. crushed hard peppermint candies (such as candy canes)
Directions
To prepare cookies: Preheat oven to 350 degrees and line baking sheets with parchment paper.
In a medium bowl, whisk together flour, cocoa, salt, baking powder and baking soda, and reserve.
In a bowl of an electric mixer on medium-high speed, beat 1/2 cup butter until creamy, about 1 minute. Add granulated sugar and beat until light and fluffy, about 2 minutes. Add egg and vanilla extract, and beat until thoroughly combined. Reduce speed to low, add flour mixture and mix until just incorporated.
Roll dough into 1-inch balls. Place dough 2 inches apart on prepared baking sheets, flattening dough slightly. Bake until cookies are set and dry-looking, about 10 minutes. Remove from oven and cool 2 minutes before transferring cookies to a wire rack to cool completely.
To prepare topping: In a bowl of an electric mixer on medium speed, combine 3 tablespoons butter and powdered sugar, and beat until creamy. Add peppermint extract and enough milk (or cream), 1 tablespoon at a time, and mix until smooth.
Spread icing across the top of each cookie, then press iced cookies into crushed peppermint candies.