
A delicious classic! Sunny yellow cake with a fudgey chocolate frosting made form scratch!
Place oven rack in the lower third of oven and preheat oven to 350 degrees. Use a paper towel to wipe sides and bottom of two non stick 9" cake pans with butter, then dust with flour. This prevents sticking.
Place four egg yolks in a small bowl, and two egg whites into a larger bowl. (discard remaining egg whites). Set bowls aside
In a bowl, place flour, baking powder, baking soda and salt. Whisk to combine well, set aside. In the bowl of a stand mixer (or large bowl using a hand mixer) cream butter and sugar at medium speed until fluffy (3-4 minutes) Scrape the sides of the bowl with spatula. Turn mixer to medium speed add egg yolks one at a time, mixing until well incorporated.
Add vanilla paste or extract, mix well.
On low speed: Add half the dry ingredients and half the buttermilk, mix until well incorporated. Add remaining dry ingredients and buttermilk.
Using a hand held mixer on high speed, beat egg whites and cream of tartar until stiff peaks form. Gently fold egg whites into batter. Don't over mix or you'll lose that fluffiness!
Pour batter equally into cake pans, tap on the counter to remove any bubbles. Bake for a total of 30 minutes, but at 15-18 minutes cooking time you're going to need to tent cakes with foil to prevent browning (common with yellow cakes). At 25 minutes, use a toothpick to check cakes. I like to check early to avoid over baking. When toothpick comes out clean, cakes are done.
Remove from oven, immediately use a knife to separate cakes from sides of pans. Allow to cool. When cool, gently flip cake pans and release cakes. Make frosting.
In a bowl, use a hand mixer with a whisk attachment to beat butter until creamy (two minutes) Add powdered sugar, cocoa powder, heavy cream, sea salt and vanilla. Beat on low for 30 seconds then increase to high speed and beat for another minute. Frosting should be thick and creamy, if it's not thick enough, add a tablespoon of powdered sugar until desired consistency is achieved. If it's too thick add a tablespoon of cream until desired consistency is achieved.
When cakes are completely cooled, frost the top of one cake, set other cake on top. Frost top and sides of cake. Serve!
I like to decorate my cakes using fresh flowers. I place a small circle of parchment paper on top so the flowers don't actually touch the frosting. You can also use, sprinkles, berries, or dust with powdered sugar once frosting sets up.