The cookies are incredibly moist and chocolaty. Add the marshmallow and chocolate frosting and you have a sweet and sinful treat.
Adapted from Martha Stewart Cookies
1 3/4 cups all purpose flour
3/4 cup unsweetened cocoa powder
1/2 tsp baking soda
1/2 t coarse salt
1/2 cup (1 stick) unsalted butter, room temperature
1 cup granulated sugar
1 large egg
1/2 cup whole milk
1 t vanilla
about 15 marshmallows, halved crosswise (just cut them in half with some kitchen shears or clean sharp scissors)
Preheat oven to 375 degrees F.
Make Cookies: sift together flour, cocoa, baking soda and salt into a bowl.
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.
Using a 1 3/4 inch cookie scoop, drop dough onto baking sheets lined with parchment paper, spacing them 2 inches apart. Bake cookies, rotating sheets halfway through, until firm, 8-10 minutes. Immediately press a marshmallow half on top of each cookie. Bake until marshmallows begin to melt, 2 minutes more. Let cool completely on sheets on wire racks.
Chocolate Satin Frosting
from Joy of Cooking
6 oz unsweetened chocolate
1 cup evaporated milk
1 1/2 cups sugar
6 T unsalted butter, cut into small pieces
1 t vanilla
Roughly chop chocolate. Set aside.
In small saucepan, bring evaporated milk to boil. Remove from heat and add chocolate pieces, without stirring. Cover and set aside for exactly 10 minutes. Scrape into bowl over mixer or food processor and add sugar, butter and vanilla. Process until smooth. Transfer to a bowl and let sit in refrigerator until it reaches desired consistency (I let mine sit about 15 minutes)
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.