Preheat oven to 350 F. Lightly grease and flour an 8” round cake pan.
In a large bowl, combine the eggs, buttermilk, vegetable oil, vanilla and vinegar.
In a medium bowl combine the dry ingredients including flour, sugar, baking powder, cacao powder and salt. Stir until well combined.
Add the mixed dry ingredients into the large bowl with the wet ingredients. Using an electric mixer, beat for about 1 minute. Then, using a toothpick, start adding food coloring to your cake until you reach the desired color. Continue to beat the batter with a mixer for about 1 more minute.
Pour the batter into your greased and floured cake pan. Bake for about 45-50 minutes. Your cake is done when it you insert a toothpick in the center and it comes out clean.