Begin by preheating your oven to 350°F (175°C). Spread the white chocolate evenly on a parchment-lined baking sheet. Bake for about 10-15 minutes, stirring every 5 minutes, until it turns golden brown. Keep a close eye on it to prevent burning. Once caramelized, remove it from the oven and set aside to cool.
In a medium saucepan over low heat, melt the unsalted butter and finely chopped dark chocolate together. Stir until smooth and remove from heat.
In a mixing bowl, whisk together the granulated sugar and eggs until well combined. Add in the melted chocolate mixture, vanilla extract, and buttermilk, mixing until smooth.
In another bowl, sift together the all-purpose flour, cocoa powder, salt, and baking powder. Gradually fold the dry ingredients into the wet mixture until just combined, being careful not to overmix.
Pour half of the brownie batter into your prepared baking pan, then drizzle half of the caramelized white chocolate on top. Use a knife or toothpick to create a swirl effect. Repeat with the remaining batter and caramelized white chocolate.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Avoid overbaking to maintain that fudgy texture!
Allow the brownies to cool in the pan for at least 15 minutes. Then, lift them out using the parchment paper and let them cool completely on a wire rack. Cut into squares and enjoy!
