Step 1: Preheat & Prepare the Pan
Preheat your oven to 350°F (175°C). Grease and line an 8×8 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal. Set aside.

Step 2: Melt Butter and Chocolate
In a large microwave-safe mixing bowl, add the melted butter and chopped semi-sweet chocolate. Microwave in 30-second intervals, stirring between each, until fully melted and smooth. Let cool slightly.

Step 3: Mix in Sugar & Wet Ingredients
Whisk the granulated sugar into the butter-chocolate mixture until well combined.
Add the eggs, one at a time, whisking well after each addition.
Stir in the vanilla extract, white vinegar, and red gel food coloring. Mix until the color is evenly distributed.

Step 4: Sift and Add Dry Ingredients
In a separate bowl, sift together the cocoa powder, all-purpose flour, and salt.
Gradually fold the dry ingredients into the wet mixture using a rubber spatula. Mix just until no dry streaks remain—do not overmix.

Step 5: Add Optional Mix-ins
If using, fold in the white chocolate chips for added sweetness and texture.

Step 6: Bake
Pour the brownie batter into the prepared pan. Use a spatula to spread it evenly into the corners.
Bake in the preheated oven for 30–35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs (not wet batter).

Step 7: Cool and Slice
Allow the brownies to cool completely in the pan before lifting out with parchment and slicing.
For an optional finishing touch, drizzle melted white chocolate over the cooled brownies before slicing