In a medium sized mixing bowl beat together the brownie mix, melted butter, water and egg.
Spread into the bottom of the prepared pan and bake for 25 minutes.
Sprinkle the marshmallows over the top and bake for an additional five minutes.
Remove from the oven and cool. In a medium sized saucepan combine the 1 stick of butter, 4-6 tablespoons of milk, powdered sugar, cocoa powder and bring to a boil over medium heat.
Once the frosting comes to a boil add in the pecans and vanilla.
Pour the warm frosting over the top of the cake and marshmallows.
Allow the cake frosting to sit for an hour and then cut and serve!
Get The Daily Update!
Be among the first to get breaking news, weather, and general news updates from News 9 delivered right to your inbox!