In a medium saucepan, melt the butter over medium low heat. Add coconut oil and chopped chocolate and reduce heat to low. Stir until chocolate is melted and smooth, adding in the cocoa powder as you stir. When smooth, add the dark brown sugar and stir until it dissolves slightly, then remove from heat.

In a mixing bowl, using a hand-held electric mixer, beat the eggs for about 1 minute or until frothy. Gradually add the granulated sugar and continue beating for 5 minutes or until thick and frothy. Beat in the vanilla and the salt.

Fold the melted chocolate mixture into the egg mixture, then fold in the flour.

Pull from oven and sprinkle chocolate chips over hot brownies so that they melt just enough to adhere.

Let cool completely at room temperature (or plunge into an ice bath if you prefer), then chill thoroughly. To remove from pan, loosen sides without parchment gently with a knife, then pull up on parchment and take brownies out of the pan. Cut into squares.