• ¾ cup butter, at room temp. (no margarine!)
  
• 2 Cups granulated sugar (NOT SUPERFINE, i.e. CASTOR SUGAR)
• 1/3 Cup neutral flavored vegetable oil (NOT SUNFLOWER OIL, WHICH IS CARCINOGENIC ONCE COOKED)  
• 4 room egg yolks, at room temp. (reserve the egg whites)
• 1 Tble. vanilla extract, best quality (one can substitute 1 ½ tsp. or equal parts vanilla extract and best quality imitation butter flavoring)  
• 3 cups/ 12 ounces cake flower (one may substitute 20 grams cornstarch with 93 grams AP flour, sifted twice)
• ¾ tsp. salt
• 2 tsp. baking powder
• ½ tsp. baking soda
  
• 1 Cup buttermilk (also at room temp.)
• 4 reserved egg whites, at room temp.

METHOD:

1. Cream together the butter, sugar, and oil on medium to high speed until light and fluffy (about 5 minutes).
   
2. Beat in egg yolks one at a time until fully incorporated, followed by the vanilla extract and butter flavoring.
3. Sift together the dry ingredients.  If making substitute-cake flour, sift it together at least twice beforehand.
4. Beginning-and-ending with the flour, alternate between the flour and the buttermilk by adding 1/3 flour and ½ the buttermilk in each addition.  Stir until almost combined.  Streaks of flour is okay!  One doesn’t want an overworked batter.
5. Using a medium-sized bowl and a hand-mixer, whip the reserved egg white to stiff peaks.  Gently fold these into the batter in thirds.  Occasional streaks or minute pieces of egg white is okay since they will bake-out and add additional leavening to the cake when baked.  Also ensure your rubber scraper is pliant and not too stiff to scrape the sides of the bowl.  Personal note: I sure could have used an extra bowl from Kitchen Aid to save time and energy whilst making this cake; but, a smaller one I can fit inside the stander aluminum bowl.
6. Divide mixture between prepared pans and bake in an oven (on middle rack) preheated to 350-degrees: 40 to 45 minutes for a 9" x 13" sheet cake pan; 36 to 42 minutes for 9" round pans; 38 to 44 minutes for 8" round pans, or 24 to 30 minutes for cupcakes. Ensure that the round cake pans are at least 2-inches high!
   
7. The center of the cake should feel firm when gently pressed, and a toothpick inserted into the center should come out clean or with just a few moist crumbs.  Allow cakes to cool completely in pans before removing, assembling and icing.