Preheat your oven to 325°F (163°C) and prepare a 9x9 inch pan by greasing or lining it with parchment paper.

In a double boiler, melt chopped white chocolate bars and unsalted butter over medium-low heat until smooth, about 5-7 minutes.

In a bowl, whisk together eggs, egg yolks, granulated sugar, and vanilla extract until pale and combined, about 2-3 minutes.

Pour the melted chocolate and butter mixture into the egg mixture and whisk until fully incorporated.

Sift in the flour and salt over the chocolate mixture and fold gently until just combined.

Pour the batter into the prepared pan and bake for 29-33 minutes; check for doneness with a toothpick.

Allow the brownies to cool in the pan for about 30 minutes, then cut into 16 squares.