Preheat your oven to 350°F Line an 8x8-inch square baking pan with a strip of parchment paper, and set aside.
In a large bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and cocoa powder.
1 & ¼ cup all-purpose flour, ¾ cup granulated sugar, ¼ teaspoon baking powder, ½ teaspoon baking soda, ¼ teaspoon salt, 3 tablespoons cocoa powder
In a separate bowl, whisk together the vegetable oil, buttermilk, eggs, red food coloring, vanilla extract, and white vinegar.
½ cup vegetable oil, ⅔ cup buttermilk, 2 large egg, 1 tablespoon red food coloring, 1 teaspoon vanilla extract, 1 teaspoon white vinegar
Add the dry ingredients to the wet ingredients and mix until just combined. Be careful not to overmix. Pour the batter into the prepared baking pan and spread it evenly.
Bake in the preheated oven for 25-30 minutes or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.