Preheat the oven to 325 degrees. Line a 13x9" baking dish with foil or parchment, and lightly grease with melted butter, oil or cooking spray.
Melt the butter in a large pan over low heat. Once melted, add the sugar and cocoa powder and stir well to combine. Continue stirring until the sugar starts to melt and the mixture is very warm to the touch. Remove from heat and stir in the vanilla extract and salt, then set aside to cool slightly, about 10 minutes.
Add the eggs to the brownie batter 1 at a time, stirring well after each addition.
4 large eggs
Add the flour, and stir just until incorporated (about 30 strokes or so). Fold in the 1 cup of chocolate chips, then pour into the prepared baking dish and spread evenly.
1 cup all purpose flour, 1 cup dark chocolate chips
Bake for 30-25 minutes or until a toothpick inserted into the center comes out with moist crumbs (not wet batter). Cool completely on a wire rack. This may be done up to a day in advance.
Prepare the ganache:
Fill a large sauté pan with about 2-3 inches of water and bring to a low simmer over medium heat. Reduce the heat to low. Place the 8 ounces of dark chocolate chips and the heavy cream in a heat proof bowl, then place in the simmering water. Stir until the chocolate has melted and the mixture has emulsified. If at any point the water gets too hot, remove the chocolate from the water and lower the heat so that the ganache doesn't break.
8 ounces dark chocolate chips, 1 cup heavy cream
Allow the ganache to thicken until it's spreadable (about 5-10 minutes), then pour over the cooled brownies and spread evenly. Sprinkle with flaky sea salt, then let stand until the ganache has set, about 1-2 hours at room temperature or 30 minutes to 1 hour in the refrigerator. Slice into squares with a very sharp knife, and wipe it clean in between cuts. Serve and enjoy!
Notes
Pro tip: Allow the brownies to cool completely before topping with the ganache. From there, make sure the ganache is set before slicing.
Chocolate note: Dark chocolate chips (60–70%) work best for the ganache. You may substitute an equal amount of finely chopped dark chocolate baking bar, or use a combination of semi-sweet and bittersweet chocolate for a balanced ganache.
Slicing the brownies. Make sure the ganache is completely set. Cut the brownies with a sharp knife and wipe it off in between to achieve nice clean slices.
Storing. Refrigerate leftovers in an air tight container for up to 5 days. Allow to come to room temperature before serving for best results.