01 -
Preheat the oven to 350°F (175°C). Line an 8x8-inch metal baking pan with foil or parchment paper and spray lightly with nonstick cooking spray. Avoid using glass or ceramic pans for this recipe to ensure brownies cook evenly.
02 -
In a microwave-safe bowl, combine the semisweet chocolate chips, unsweetened chocolate, and butter. Microwave for 1 minute and stir. Continue microwaving in 30-second intervals, stirring after each, until fully melted and smooth. Let cool slightly.
03 -
In a large mixing bowl, use an electric mixer to beat the eggs, egg yolk, and sugar on medium-high speed until the mixture is light, thick, and ribbony, about 3 to 5 minutes.
04 -
Add the vanilla extract and cooled chocolate-butter mixture to the beaten eggs and gently stir with a rubber spatula. Fold in the flour and salt until just combined, taking care not to overmix.
05 -
Pour the batter into the prepared baking pan and smooth the top. Bake for 35 to 40 minutes, or until a tester inserted into the center comes out with moist crumbs. Avoid overbaking, as brownies will continue to set while cooling.
06 -
Allow the brownies to cool completely to room temperature before slicing. Serve at room temperature or chilled for an even fudgier texture.