📖 Instructions

1. Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round baking pans. Line the bottoms with parchment paper rounds. This is super important – nobody wants a cake stuck to the pan!
2. In a medium bowl, whisk together the cake flour, baking powder, baking soda, and salt. Make sure everything's evenly distributed; you don't want pockets of baking powder in your cake.
3. In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and sugar until light and fluffy. This usually takes about 3-5 minutes on medium speed. Don’t rush this step, it’s key to a good cake texture!
4. Beat in the eggs one at a time, then stir in the vanilla bean paste. Scrape down the sides of the bowl as needed to ensure everything is well combined. Vanilla bean paste smells heavenly, doesn't it?
5. In a liquid measuring cup, combine the buttermilk and sour cream. These two ingredients work wonders to keep the cake moist.
6. Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk mixture, beginning and ending with the dry ingredients. Mix until just combined. Be careful not to overmix; overmixing can lead to a tough cake.
7. Divide the batter evenly between the prepared baking pans. Smooth the tops with a spatula. I like to use a kitchen scale to make sure the pans are even, but eyeballin' it works too.
8. Bake for 30-35 minutes, or until a cake tester inserted into the center comes out clean. Keep an eye on them; ovens vary!
9. Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely. Remove the parchment paper. Cooling upside down helps to flatten the cake layers.
10. While the cakes are cooling, prepare the vanilla buttercream. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter until smooth and creamy. I like my butter to be slightly cooler than room temperature for the best consistency.
11. Gradually add the powdered sugar, one cup at a time, beating well after each addition. Then, beat in the vanilla bean paste and milk until the frosting is smooth and fluffy. Adjust the amount of milk to reach your desired consistency. Taste and add more vanilla bean paste if needed; you're the boss here!
12. Once the cakes are completely cool, level them with a serrated knife if necessary. This is optional, but it helps to create a perfectly even cake.
13. Place one cake layer on a serving plate or cake stand. Spread a generous layer of vanilla buttercream over the top. I like to use an offset spatula for this.
14. Top with the second cake layer and frost the entire cake with the remaining buttercream. Get creative with your decorating; swirls, rosettes, sprinkles – the sky's the limit!
15. Chill the cake for at least 30 minutes before serving to allow the buttercream to set. This makes it easier to slice and serve neatly. And hey, it gives you a chance to clean up a bit!