Preheat the oven to 350°F (175°C). Grease and flour a bundt pan or a round cake pan thoroughly to prevent sticking.
Mix the dry ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
Cream the butter and sugar: In a large bowl, beat the butter and sugar until light and fluffy. Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
Combine wet and dry: Add the dry mixture to the wet ingredients in three batches, alternating with the buttermilk. Mix until the batter is smooth and fully combined.
Divide and color the batter: Separate the batter evenly into three bowls:
Leave one bowl plain (vanilla).
To the second bowl, mix in cocoa powder and black food coloring.
To the third bowl, mix in orange food coloring until vibrant.
Layer and swirl: Spoon dollops of each batter randomly into the prepared pan. Once all the batter is added, use a knife or skewer to swirl the colors slightly to create a marbled effect.
Optional: Sprinkle semi-sweet chocolate chips over the top for added richness.
Bake: Bake for 40–45 minutes or until a toothpick inserted into the center comes out clean.
Cool: Let the cake cool in the pan for 15 minutes before transferring to a wire rack to cool completely.
