Instructions

For the Brownies

1. Preheat oven to 350°F. Line a 13x9 baking dish with parchment paper. Set aside.
2. In a medium sized saucepan, melt butter over medium heat. Remove from heat and add in chocolate chips and sugar.
3. Stir until chocolate is completely melted. Add in eggs, one at a time, stirring completely after each addition. Stir in vanilla.
4. Add the cocoa powder, flour, salt, and baking powder. Using big strokes, stir in JUST until mixed and no longer see dry ingredients. DO NOT BEAT OR OVER STIR.
5. Pour batter into dish and bake for about 22-24 minutes. Remove from oven and sprinkle with mini marshmallows.
6. Place pan back in oven and bake for 90 seconds, until marshmallows puff in size. Remove from oven and cool.

For the Topping

1. In a small saucepan, melt butter over medium heat. Once melted, whisk in the buttermilk and cocoa powder.
2. Keep whisking until mixture begins to boil, then remove from heat.
3. In a large mixing bowl, add powdered sugar. Pour chocolate mixture in the bowl and using the whisk attachment, beat mixture until fully combined and smooth. This will take several minutes, you don't want the sugar grainy.
4. Pour warm frosting over brownies (it's okay if the brownies aren't completely cooled yet).
5. Let set and cool, completely.