Step 1

For the Yellow Cake: Preheat oven to 350 degrees F. Set oven rack in the lower third of oven.

Step 2

Over a large bowl, sift together cake flour, baking powder, baking soda and salt with a fine mesh strainer. Set aside.

Step 3

In the large bowl of an electric stand mixer or with a handheld electric mixer, whip butter on medium speed for 1-2 minutes. Add granulated sugar and beat for 4-5 minutes on medium speed. Mix in vanilla. One at a time, add eggs and egg yolks, mixing just until combined in between additions. Scrape down the sides of the bowl as needed.

Step 4

Add 1/3 of the flour mixture to the batter and mix just until combined, scraping down the sides of the bowl as needed. Whisk milk and sour cream together. Mix in 1/2 of the milk mixture. Mix in another 1/3 of flour mixture, followed by the milk mixture, and the remaining flour mixture, mixing just until combined. Stir batter to make sure all ingredients are well combined.

Step 5

Grease cake pans (I use nonstick cooking spray) and line bottoms with a parchment round. Grease parchment and sides of pan again. If your pans are prone to sticking, consider flouring them as well.

Step 6

Divide batter evenly between the two pans. Drop each pan from about 3 inches onto the counter to minimize air bubbles while baking.

Step 7

Bake for 25-28 minutes, until lightly golden around edges and a toothpick inserted in the center comes out with moist crumbs.

Step 8

Let cakes rest in the pans for 10 minutes before gently inverting them onto a cooling rack to cool completely before frosting.

Step 9

For the Vanilla Frosting: In the large bowl of an electric stand mixer or with a handheld electric mixer, add butter. Beat on medium speed for 3 minutes, or until smooth and lightened in color.

Step 10

Add powdered sugar, 1/2 cup at a time. After each addition, gradually turn mixer to the highest speed setting and beat for 10 seconds to lighten the frosting. Mix in vanilla.

Step 11

Add milk, heavy cream or half-and-half until the frosting has reached the preferred consistency. For a firmer frosting, add more powdered sugar (1/4 cup at a time). For a softer frosting, add more milk or cream (1 Tbsp. at a time).

Step 12

Frost your cake as desired. I love this video tutorial with helpful tips.

Step 13

Enjoy!