Rocky road brownies

adapted from: Liz M. 1 c. melted butter 2 c. sugar 1/3 c. cocoa powder 1 1/2 c. all-purpose flour 2 tsp. vanilla         1 tsp. salt 4 eggs chopped walnuts or pecans, opt. 1 (10 oz.) bag mini marshmallows Icing: 1/2 c. butter, softened 1/4 c. cocoa powder 1/4 c. evaporated milk, more or less 1 tsp. vanilla 3 c. powdered sugar or 1 container store-bought milk chocolate frosting Preheat oven to 350 degrees.  Combine melted butter, sugar and cocoa powder.  Add flour, vanilla, salt, eggs and nuts.  Whisk together until completely smooth and well combined.  You can either use a hand mixer or a whisk for this.  Pour into a lightly greased 9x13 pan and bake for 25 minutes.  Remove from oven and top with the marshmallows.  Return to oven and bake for 5 minutes or until marshmallows are puffed up.  Allow to cool and then  spread homemade icing or store-bought frosting over the top.  To make the icing:  Using a hand mixer, beat butter until fluffy.  Add the cocoa powder and vanilla and mix until well combined.  Gradually add the powdered sugar and mix until smooth and creamy, adding evaporated milk as you go to reach desired consistency.