Preheat the oven to 350 F. In a large bowl, whisk together flour, sugar, cocoa powder, salt, and baking soda. Add in eggs, melted butter, and vanilla extract, and mix until smooth.
Pour the brownie batter into a greased 8-inch square baking dish. Bake for 20-25 minutes. Let cool completely.
For the frosting, mix the butter with powdered sugar, milk, and mint extract until smooth. Add in the green food coloring, and mix until fully green. Fold in the chocolate chips.
Frost the brownies, and cut into squares.
