- 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 well combined and free of lumps. 
- In a separate bowl, combine the buttermilk, vegetable oil, eggs, vanilla extract, and gel food coloring. Mix with an electric mixer until thoroughly blended and the mixture is smooth, with a rich red hue and a slight sheen. 
- Pour the wet mixture into the dry ingredients. Use the mixer on low speed or a spatula to gently fold everything together until just combined. The batter should be thick, smooth, and velvety. 
- Pour the batter into your prepared cake pan, spreading it evenly with a spatula. Tap the pan lightly on the counter to release any air bubbles and level the top. 
- Bake in the preheated oven for 25-30 minutes, or until the top is set and a toothpick inserted into the center comes out clean. The cake should be deep crimson and slightly springy to the touch. 
- 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, allowing the color to deepen and the crumb to set. 
- Meanwhile, prepare the frosting by beating the softened cream cheese and butter together until creamy and smooth. Gradually add the powdered sugar, beating until fluffy and spreadable. 
- Once the cake is fully cooled, spread a generous layer of cream cheese frosting over the top and sides of the cake. Use a spatula to create a smooth, inviting finish. 
- Slice to reveal the deep red interior, and enjoy the moist, velvety crumb with every bite. The vivid color and rich flavor make it perfect for special occasions or whenever you want to impress.