Preheat oven to 350F
Prepare 8x8 inch pan with parchment paper – have the paper overhang the edges on just two sides. This will make it easy to pop the brownies out once baked. Set aside.
Heat up the butter so it melts and is hot, without it browning. Either in a saucepan or in the microwave.
Stir in about 3 tbsp of the white sugar, you can use a spoon or whisk. Once it is mixed in as much as possible, add approximately 3 more tablespoons of the white sugar and mix in as thoroughly as possible. The idea is to dissolve as much of the white sugar as possible into the butter – this is the secret to the crackly shiny surface on brownies. When no more sugar can be dissolved, add the rest of the white sugar and all of the brown sugar. Combine to get a homogenous mixture. You will have a very thick mixture.
If you were using a saucepan, transfer the contents to a mixing bowl for easier stirring.
Add in the eggs, vanilla, and vinegar. Stir to thoroughly combine.
Stir in the oil completely.
Mix in the red food coloring until the batter is completely red.
Sift in the cocoa, flour and baking powder. Stir well until a uniform batter comes together.
If using white chocolate chips, stir in ½ cup of them.
Pour into the prepared 8x8 pan and smooth out the top with a rubber spatula. If using white chocolate chips you can sprinkle ¼ cup on top.
Place in the preheated oven at 350F and bake for 20-25 minutes. A toothpick should come out relatively clean.
Allow the brownies to completely cool in the pan, about an hour.
Using the overhanging edges of the parchment paper, remove the brownie square from the pan to a cutting board. Cut into 9 equal squares and enjoy!