I got the recipe from here.
1 chocolate cake mix (I used Pillsbury devils food)
1/2 cup butter-flavored shortening (I used butter because I didn't have any)
2 eggs
12 large marshmallows
1/2 c. melted butter
1/3 c. unsweetened cocoa powder
1/3 c. evaporated milk (I used regular 1% )
1 lb. powdered sugar
1 tsp. vanilla
Instructions:
Preheat oven to 350. Combine cake mix, eggs, and shortening in the bowl of a heavy-duty mixer and mix until well combined. Drop dough by the tablespoon onto a baking sheet and bake for about 8-10 minutes or until the cookies appear done but are still soft in the center.
While the cookies are baking, use a pair of kitchen shears to cut each marshmallow in half. When the cookies have baked, remove the pan from the oven and place a marshmallow half on each cookie, cut side down. Return the pan to the oven for about 2 minutes. Remove from oven and very gently push each marshmallow down. Allow to cool completely and repeat with remaining cookie dough.
When the cookies have cooled completely, combine the powdered sugar and cocoa powder in a large bowl. Add melted butter, vanilla, and evaporated milk and beat on high until smooth, light, and fluffy. Transfer the frosting to an icing bag fitted with a large tip and swirl onto the cookies. Makes 24 cookies.
And these are what hers looked like. The shortening makes a difference in how they turn out. I think mine stayed poofier because of the butter, but still are amazing. I also think these would be devine with brownie cookies (made from a brownie mix)