Using three different kinds of chocolate gives these brownies an intense, fudgy, chocolate flavor. Semi-sweet and unsweetened chocolate bars add a fudgy, rich texture. When you add in unsweetened cocoa powder, you will have a deep, complex, chocolate flavor. Whipping the eggs with the sugar until it reaches a thick, fluffy consistency is the secret to the BEST brownies. It creates an amazing fudgy texture. Don't skip this step.
Preheat the oven to 350°F. Line an 8 inch by 8 inch baking pan with parchment paper.
Place the butter, and chopped chocolate (bittersweet and unsweetened) in a microwavable bowl. Microwave on low power in 15 second intervals until melted. Stir frequently between intervals.
Place the eggs and sugar in a mixing bowl. Beat on high speed for 7 to 8 minutes until light in color, thick, fluffy, and almost tripled in size. You will know it is ready when you lift the beaters and the batter falls back onto the surface, leaving a ribbon-like pattern for a few seconds.
Stir about ⅓ of the egg batter into the melted chocolate to lighten the chocolate then stir in the vanilla.
Pour the chocolate mixture into the egg batter and use a wide spatula to fold the chocolate into the batter.
Combine the flour, cocoa powder, and salt in a bowl. Whisk or sift to remove all the lumps then fold the flour mixture into the batter.
Spread the batter into the prepared pan. Bake for 35 to 40 minutes. The top will be slightly cracked and the edges will appear set. A toothpick inserted in the middle should have some moist, sticky crumbs (the toothpick shouldn’t be wet but it shouldn’t be clean). If you have an instant read thermometer, it should read 193°F to 198°F.
Notes
Let them cool: The center of the brownies will seem underbaked, but it will set up as the brownies cool.Use a thermometer (if you have one): An instant-read thermometer isn’t necessary, but it’s helpful. It guarantees perfectly baked brownies, not overcooked, not undercooked.Toothpick test works too: If you don’t have a thermometer, check doneness with a toothpick. Look for moist, sticky crumbs (not wet batter, and not a clean pick).Want even more chocolate? Stir in 8 to 10 ounces of milk chocolate chips before baking to turn these into quadruple chocolate brownies.