Preheat your oven to 180°C (350°F). Grease a 23cm (9-inch) round cake pan and line it with parchment paper for easy removal.
In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, and salt until evenly combined. This creates a dry, powdery mixture that forms the base of your batter.
In another bowl, combine the buttermilk, vegetable oil, eggs, vanilla extract, and red gel food coloring. Whisk until the mixture is smooth and vibrant red in color, with no streaks.
Pour the wet mixture into the dry ingredients and gently fold everything together using a spatula. Mix just until the batter is smooth, thick but silky, and uniformly colored.
Pour the batter into the prepared cake pan, spreading it out evenly with your spatula. The batter should fill the pan smoothly without lumps.
Bake in the preheated oven for about 25-30 minutes, until the edges are set and a toothpick inserted into the center comes out clean with no wet batter attached.
Remove the cake from the oven and let it cool in the pan for about 10 minutes. Then, transfer it to a wire rack to cool completely, watching the deep crimson color set as it cools.
Once cooled, spread a generous layer of cream cheese frosting over the top and sides of the cake, smoothing it out with a spatula for a polished finish.
Slice into the velvety, rich cake to reveal its deep red color and tender crumb—perfect for sharing and making a dramatic statement at any celebration.
