For the Cake:

1. Preheat the Oven:

   – Preheat the oven to 325°F (165°C). Grease and flour three 8-inch cake pans, and line the bottoms with parchment paper.

2. Mix Dry Ingredients:

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

3. Mix Wet Ingredients:

   – In another bowl, combine the buttermilk, vegetable oil, and vanilla extract. Set aside.

4. Make the Batter:

   – In a stand mixer, beat the softened butter and cream cheese until smooth.

   – Gradually add the sugar and mix on medium speed for 2-3 minutes.

   – Add the eggs one at a time, mixing until the yolk disappears after each addition.

   – On low speed, alternate adding the dry ingredients and the wet ingredients, beginning and ending with the dry ingredients (3 additions of dry, 2 of wet). Mix just until combined—do not overmix.

5. Bake the Cakes:

   – Divide the batter evenly between the prepared pans.

   – Bake for 25-28 minutes, or until a toothpick inserted into the center comes out clean or with a few crumbs.

   – Let the cakes cool in the pans for 5-10 minutes, then turn them out onto a wire rack to cool completely.

For the Vanilla Buttercream:

1. Cream the Butter:

   – Beat the softened butter until smooth. Add the vanilla extract and mix until combined.

2. Add Sugar and Milk:

   – Add half of the powdered sugar and most of the milk. Beat on medium speed until incorporated.

   – Add the remaining powdered sugar and milk. Beat for 3-4 minutes, scraping the bowl as needed.

   – Reduce the mixer speed to low (#2 on a KitchenAid) for 1-2 minutes to eliminate air bubbles and create a smooth texture.

3. Adjust Consistency:

   – If the frosting is too thin, add more powdered sugar. If too thick, add a bit more milk.

Assembly:

1. Layer the Cake:

   – Place the first cake layer on a cake plate or pedestal. Spread a layer of buttercream on top. Repeat with the remaining layers.

2. Crumb Coat:

   – Fill in any gaps between the layers with buttercream and apply a thin crumb coat. Chill the cake in the freezer for 10-15 minutes (or in the refrigerator for longer) to firm up the frosting.

3. Frost and Decorate:

   – Apply the final coat of frosting. Use a bench scraper or spatula to smooth the sides. Decorate as desired (e.g., piping borders or roses).

—

Notes:

– Cake Flour Substitute: For each cup of all-purpose flour, remove 2 tablespoons and replace with 2 tablespoons of cornstarch. For this recipe, use 3 cups of all-purpose flour, remove 6 tablespoons, and add 6 tablespoons of cornstarch. Whisk to blend.

– Buttermilk Substitute: Add 1 tablespoon of vinegar or lemon juice to a measuring cup, then add milk to the 1-cup mark. Stir and let sit for 5 minutes before using.