Combine flour, salt, and cocoa powder in a medium bowl. Set aside.
Cream butter and sugar until fluffy (4 mins). Add sour cream, mix for 1 min. Add oil, mix for 1 min. Add eggs one at a time, beating well after each addition.
Next, pour in the buttermilk, vinegar, and vanilla and thoroughly mix
Add food coloring until you reach the desired color.
Slowly add flour mixture to wet ingredients. Mix baking soda and powder with water. Gently fold into cake batter. Scrape sides of mixing bowl while mixing.
Divide batter between pans evenly. Tap pans on countertop to release bubbles. Bake at 350℉/177℃ for 25-30 mins. Check doneness with a knife/toothpick in center. Clean = done.