• 1 3/4 cups all-purpose flour
• 3/4 cup cocoa powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon salt
• 1/2 cup (1 stick) unsalted butter, softened
• 1 cup sugar
• 1 large egg
• 1/2 cup milk
• 1 teaspoon pure vanilla extract
• 12 large marshmallows, cut in half horizontally

1. Preheat oven to 375°.
2. In a medium bowl, whisk together flour, cocoa powder, baking soda, and salt; set aside.
3. In the bowl of an electric mixer fitted with the paddle attachment, cream together butter and sugar until light and fluffy, about 2 minutes.
4. Add egg, milk, and vanilla, and beat until well combined.
5. Add reserved flour mixture; mix on low speed until combined.
6. Using a tablespoon or 1 3/4-inch ice cream scoop, drop dough onto ungreased baking sheets, about 2 inches apart.
7. Bake until cookies begin to spread and become firm, 10 to 12 minutes.
8. Remove baking sheets from oven, and place a marshmallow, cut-side down, in the center of each cookie, pressing down slightly.
9. Return to oven, and continue baking until marshmallows begins to melt, 2 to 2 1/2 minutes.
10. Transfer cookies to a wire rack to cool completely before frosting.
11. Spread about 1 tablespoon of frosting over each marshmallow, starting in the center and continuing outward until marshmallow is covered.

"I LOVE these cookies. They are ooey-gooey and so good! Intense chocolate cookie with soft marshmallow guts."