Holiday Challenge Day 9 - Surprise Cookies

 As snow and ice pummel parts of the country, I find myself waxing nostalgic about winters spent growing up in Northeast Connecticut (while simultaneously thanking my lucky stars that in Florida, the temperature makes it possible for me to write this while wearing shorts and flip flops). 

Although I'm glad to live in a warm climate now, back when I was a kid, there was nothing I looked forward to more in winter than a snow day from school.  Stoked at the thought of staying home, and oblivious to the frequently bitter chill in the air, my brother and I would don our jackets, snow pants, boots and mittens and eagerly head outside for a day of play.  Snowball fights, snow fort building, sledding and tobogganing ceased only for the occasional trip back inside for fresh mittens, a bite to eat, or a warm beverage.  Too young for hot buttered rum or a nip of Rumplemints (hee hee), we settled for cups of steaming hot cocoa instead...a few mini marshmallows on top, and ahh...nirvana!

If you, like me, still find the medley of chocolate and marshmallow irresistible, the only surprise about this cookie is it's name.  After all, with a delightful combination of cake-like chocolate cookie, marshmallow, and chocolate buttercream frosting, it's no surprise at all that they're so good. 

Surprise Cookies
Makes 2 1/2 dozen
Martha Stewart Cookies

For the cookies:
1 3/4 cups all purpose flour
3/4 cup unsweetened cocoa (not Dutch-process)
1/2 teaspoon baking soda
1/2 teaspoon coarse salt
1/2 cup (1 stick) unsalted butter, room temperature
1 cup granulated sugar
1 large egg
1/2 cup whole milk
1 teaspoon pure vanilla extract
About 15 marshmallows, halved crosswise

1. Preheat oven to 375 degrees.

2. Sift together flour, cocoa powder, baking soda and salt in a bowl.
3. Put butter and sugar into the bowl of an electric mixer fitted with the paddle attachment. Mix on medium-high speed until pale and fluffy, about 2 minutes. Reduce speed to medium-low; mix in egg, milk, and vanilla. Mix in flour mixture, 1/2 cup at a time, until combined.
4. Using a 1 3/4 inch ice cream scoop, drop dough onto baking sheets lined with parchment paper, spacing 2 inches apart. Bake cookies, rotating sheets halfway through, until firm, 8 to 10 minutes. Immediately press a marshmallow half on top of each cookie. Bake until marshmallows begin to melt, 2 minutes or more. Let cool completely on sheets on wire racks.

For the frosting:
3 cups confectioners sugar
6 tablespoons unsalted butter, room temperature
1/4 cup plus 1 1/2 teaspoons unsweetened cocoa powder (not Dutch-process)
1/4 cup plus 2 tablespoons whole milk
3/4 teaspoon pure vanilla extract

Put confectioners sugar in a medium bowl.  Melt butter with the cocoa powder in a saucepan over medium-low heat, stirring occasionally.  Add butter mixture to the confectioners sugar.  Whisk in milk and vanilla. 

Assemble the Cookies:
Spread about 1 tablespoon of frosting on top of each cookie to cover marshmallow.  Let stand until set, about 10 minutes.  Cookies can be stored in single layers in airtight containers at room temperature up to 2 days.