Preheat and Prepare: Begin by preheating your oven to 325°F (163°C). Grease and flour a bundt pan or loaf pans to ensure easy release after baking.
Mix Dry Ingredients: In a mixing bowl, whisk together the 2 ½ cups of all-purpose flour, 1 tsp baking powder, ½ tsp baking soda, ½ tsp salt, and 2 tbsp unsweetened cocoa powder. Ensure these dry ingredients are well combined.
Cream Butter and Sugar: In a large mixing bowl, beat 1 cup softened unsalted butter and 2 cups granulated sugar together until the mixture is light and fluffy. This should take about 3-4 minutes to achieve the right texture.
Incorporate Eggs: Add the 4 large eggs one at a time to the butter and sugar mixture, mixing well after each addition. This ensures a well-combined batter.
Add Wet Ingredients: In another bowl, mix 1 cup room temperature buttermilk, 2 tsp vanilla extract, 1 tbsp red food coloring, and 1 tsp distilled white vinegar. Gradually add this mixture to the batter, alternating with the dry ingredients in three additions. Mix on low until just combined to prevent overmixing.
Pour Batter: Transfer the batter to the prepared pan, using a spatula to smooth the top for an even bake.
Bake: Place the pan in the preheated oven and bake for 1 hour and 10 minutes, or until a toothpick inserted in the center comes out clean. Allow the cake to cool in the pan for 15 minutes.
Cool and Glaze: Turn the cake out onto a wire rack to cool completely. For the optional cream cheese glaze, whisk together 4 oz softened cream cheese, 1 cup powdered sugar, 2-3 tbsp milk, and ½ tsp vanilla extract until smooth. Drizzle over the cooled cake.