Preheat Oven: Set your oven to 325°F (163°C). Grease and flour a 10-inch bundt pan thoroughly to prevent sticking.

Cream Butter and Cream Cheese: In a large mixing bowl, using an electric mixer, beat the softened butter and cream cheese together until the mixture is smooth and creamy.

Add Sugar: Gradually add the granulated sugar to the mixture, continuing to beat until the mixture is light and fluffy.

Incorporate Eggs and Vanilla: Add the eggs one at a time, ensuring each egg is fully incorporated before adding the next. Mix in the vanilla extract.

Combine Dry Ingredients: In a separate bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking powder, and salt until well combined.

Alternate Adding Dry Ingredients and Buttermilk: Gradually add the dry ingredient mixture to the butter mixture in three parts, alternating with the buttermilk. Begin and end with the dry ingredients, mixing just until each addition is incorporated. Be careful not to overmix, as this can result in a denser cake.

Pour Batter into Pan: Transfer the batter into the prepared bundt pan, smoothing the top with a spatula to ensure even baking.

Bake: Place the pan in the preheated oven and bake for approximately 70-80 minutes, or until a toothpick inserted into the center of the cake comes out clean or with just a few moist crumbs attached.

Cool: Remove the cake from the oven and allow it to cool in the pan for about 15 minutes. Then, carefully invert the cake onto a wire rack to cool completely.

Serve: Once the cake has cooled, slice and serve. For an added touch, you can dust the top with powdered sugar or drizzle with a simple chocolate glaze.