Preheat the oven to 350 degrees. Grease an 88-inch glass baking dish with nonstick cooking spray.
In a large, microwave-safe mixing bowl, add the chopped baking chocolate, butter, and 1 cup of the semi-sweet chocolate chips. Microwave on high for 11/2minutes. Whisk the melted butter into the melted chocolate to make smooth chocolate 'batter'.
Whisk the sugar, vanilla, flour, cocoa powder, and salt into the butter-chocolate mixture.
Whisk the eggs into the batter. Whisk for about 1 minute, or until the batter is smooth. Fold in the remaining semi-sweet chocolate chips, the dark chocolate chips and the white chocolate chips.
Pour the batter into the greased baking dish. Bake in the preheated oven for 30 to 35 minutes until a toothpick inserted in the center comes out clean. Let cool slightly before cutting and serving.
Serve Triple Chocolate Brownies, warm for dessert.