Line your square brownie pan with parchment paper and preheat oven to 350. In a double boiler, melt your butter and chocolate chips until smooth then cool.
In a large mixing bowl, mix together eggs and sugar until light in color. Slowly incorporate the cooled chocolate and butter mixture into the eggs and sugar, whisking until smooth. Add vanilla and mix.
In a smaller bowl mix together flour, cocoa, baking soda, and salt. Add the dry ingredients into the wet ingredients and mix just until smooth. Mix in the remaining chocolate chips, pour into your baking dish and bake for 30 minutes or until a toothpick comes out clean when poked into a corner of the brownies! We want the center to remain a bit less solid as it will continue to cook.
While the brownies are cooling, make the icing. Melt your chocolate chips and butter in the same double boiler. Pour into a pyrex dish and cool in the fridge until it has set fully. Using a stand mixer, beat the frosting until it is light and fluffy. Spread generously over brownies, sprinkle with flake salt, and enjoy!