Preheat your oven to 350°F and line an 8×8-inch baking pan with parchment paper.
In a large microwave-safe bowl, melt the butter and chopped chocolate in 30-second intervals in the microwave, stirring after each interval until fully melted.
Stir the granulated sugar into the melted butter and chocolate mixture until combined. Add the eggs one at a time, beating well after each addition. Then, mix in the vanilla extract, white vinegar, and red food coloring.
In a separate bowl, sift together the cocoa powder, flour, and salt.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix. If you like, fold in white chocolate chips into the batter.
Pour the batter into the prepared pan, spreading it out evenly.
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).
Allow the brownies to cool completely in the pan before slicing them into squares.
If desired, drizzle melted white chocolate on top, let it set, and enjoy!