01 -
Preheat oven to 350°F and line an 8x8 inch baking pan with parchment paper.
02 -
In a large microwave-safe mixing bowl, combine melted butter and chopped semi-sweet chocolate. Microwave in 30-second intervals, stirring after each, until smooth and fully melted.
03 -
Add granulated sugar to the melted mixture, stirring until incorporated. Add eggs one at a time, mixing thoroughly after each addition. Stir in vanilla extract, white vinegar, and red gel food coloring until the mixture is smooth and evenly tinted.
04 -
In a separate bowl, sift together unsweetened cocoa powder, all-purpose flour, and salt.
05 -
Gradually fold the dry ingredients into the wet mixture until just combined, ensuring no streaks of flour remain. For a marbled effect or added sweetness, gently fold in white chocolate chips at this stage, or reserve to melt and drizzle over the surface after baking.
06 -
Transfer the batter to the prepared baking pan, smoothing the surface with a spatula. Bake on the center rack for 30 to 45 minutes, or until a toothpick inserted in the center emerges with a few moist crumbs.
07 -
Allow brownies to cool completely in the pan before slicing. If desired, melt and drizzle reserved white chocolate chips over the cooled brownies before serving.