Preheat your oven to 350°F (175°C) and grease and flour two 9-inch round cake pans. Set them aside.

In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.

In a large bowl, combine the buttermilk, vinegar, granulated sugar, vegetable oil, butter, eggs, and vanilla extract. Mix until smooth.

If using ube puree or purple sweet potato, stir it in to give the batter that beautiful purple hue. If you're using food coloring, add it until you achieve the desired color.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.

Divide the batter evenly between the prepared cake pans. Bake for 30–35 minutes or until a toothpick inserted into the center comes out clean. Let the cakes cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

In a medium bowl, beat together the softened cream cheese and butter until smooth. Gradually add powdered sugar and continue to beat until fluffy and smooth. Add the vanilla extract and a pinch of salt. Mix until fully combined.

Once the cakes are completely cooled, spread a layer of cream cheese frosting on top of one cake layer. Place the second cake layer on top and frost the top and sides of the entire cake with the remaining frosting.

Slice the cake into pieces and serve. Enjoy this moist, velvety dessert with a rich cream cheese frosting that’s perfect for any occasion!