Preheat your oven to 350°F (175°C). This step is crucial for achieving that perfect bake. While your oven heats up, take a 9×9 metal baking pan and line it with parchment paper, allowing for easy removal later.
In a double boiler set over medium-low heat, combine the finely chopped white chocolate and unsalted butter. Stir often as they melt together to prevent burning. You want a smooth mixture with no lumps. It should take a few minutes for the chocolate to fully melt.
While the chocolate mixture is melting, grab a large mixing bowl. In it, whisk together the granulated sugar, eggs, egg yolk, and vanilla extract until everything is well combined and slightly frothy. The frothiness indicates that you're incorporating air, which helps with the texture.
Once the chocolate mixture is smooth, slowly drizzle it into the bowl of wet ingredients, whisking constantly. This is crucial to avoid cooking the eggs. You should end up with a lovely, glossy mixture that’s well combined.
Now, add the all-purpose flour and salt to the wet mixture. Stir gently until fully incorporated. At this stage, the batter should be thick and smooth, with no dry patches remaining.
Fold in ½ cup of the white chocolate chips into the brownie batter, ensuring they are evenly distributed throughout the mixture. This adds delightful pockets of sweetness as they melt during baking.
Spread the brownie batter into your prepared baking pan, smoothing it out evenly with a spatula. Make sure to get into the corners for an even bake. Then sprinkle the remaining ¼ cup of white chocolate chips over the top for an extra layer of yumminess.
Place the pan in the preheated oven and bake for 30 to 33 minutes. Keep an eye on them; the edges should be lightly golden, and the center should be set with no jiggle. If the edges start browning too quickly, you can cover the pan loosely with foil after about 15 minutes.
Once baked, remove the brownies from the oven and let them cool completely in the pan. After cooling, lift them out using the parchment paper and slice them into squares to serve. You’ll love how easy they are to cut, thanks to the lining.
