-
1
To make the cake, preheat the oven to 350F.
-
2
Grease and flour a 9 x 13-inch baking pan.
-
3
Whisk together the flour, sugar, baking soda, and salt in a large mixing bowl.
-
4
Heat the butter, cocoa, and coffee in a medium saucepan over medium-high heat, stirring constantly, just until the butter is melted; remove from the heat, and cool slightly.
-
5
Stir the dry ingredients into the chocolate mixture until smooth.
-
6
In a medium mixing bowl, whisk together the eggs, buttermilk, and vanilla, and then add this mixture to the chocolate batter, stirring until combined.
-
7
Pour the batter into the prepared pan, and bake for 25 minutes, or until it is springy to the touch and a cake tester inserted in the center of the cake comes out mostly clean.
-
8
Allow the cake to cool for 5 minutes on a wire rack, then top with the mini morsels and miniature marshmallows.
-
9
While the cake is baking, make the icing.
-
10
Melt the butter with the cocoa, instant espresso, hot water, and cream over medium-low heat.
-
11
Bring the mixture to a boil, then remove from the heat.
-
12
Stir in the confectioners sugar, then the vanilla.
-
13
Pour the warm icing over the cake and the chocolate chips and marshmallows, top with the chopped nuts, and cool completely before serving.
