Preheat your oven to 180°C (350°F). Grease your 20cm round cake pan and line the bottom with parchment paper to prevent sticking.
Sift together the flour, cocoa powder, baking soda, and salt in a large mixing bowl until evenly combined. This ensures a light, airy crumb.
In a separate bowl, whisk the eggs, buttermilk, vegetable oil, vinegar, and vanilla extract until the mixture is smooth and fragrant, about 1-2 minutes.
Gradually pour the wet mixture into the dry ingredients, folding gently with a spatula or beating with an electric mixer on low speed. Mix until the batter is glossy, smooth, and free of lumps, about 2-3 minutes.
Add the red food coloring to the batter and mix until the color is evenly distributed, resulting in a deep crimson hue.
Pour the batter into your prepared cake pan, spreading evenly with a spatula for a flat, level surface.
Bake in the preheated oven for about 30 minutes, or until the top is set and a toothpick inserted in the center comes out clean. Your kitchen will fill with a rich cocoa aroma.
Remove the cake from the oven and let it cool in the pan for 10 minutes, then transfer to a cooling rack to cool completely. The cake should feel moist and tender to the touch.
Once cooled, carefully slice the cake horizontally if layering, or serve as is. Frost with tangy cream cheese frosting for the perfect finishing touch.
Enjoy your vibrant, velvety dark red velvet cake, perfect for celebrations or a decadent treat.