In a medium bowl, combine flour, salt, and cocoa powder. Set aside.
Preheat oven to 350 degrees F. Grease muffin/cupcake pan (or two 9-inch round baking pans) with baking spray. Or line with parchment paper, if desired. Set aside.
Cream together the butter and sugar at high speed in a stand mixer until it’s fluffy and starting to look white, about 4 minutes. Then add sour cream and mix for another minute. Followed by the oil – mix for another minute.
Add in eggs, one at a time, beating the mixture well between each addition.
Next, pour in the buttermilk, vanilla extract, and vinegar; mix thoroughly.
Add the red food coloring until the desired color has been reached.
Slowly add flour mixture into the batter. Then mix baking soda and water and gently fold into the cake batter. Scrape down the sides of the mixing bowl.
Divide the batter evenly by scooping the batter with a measuring cup. Tap the pan on the countertop to release bubbles.
Bake at 350 Degrees F for about 25-30 minutes or until a toothpick inserted in the cupcake comes out clean.
Let the cupcakes sit in their pans for about 10- 15 minutes.
Once the cupcakes have completely cooled, wrap them in plastic paper and place them in the refrigerator for at least an hour or preferably overnight. This makes applying the frosting so much easier.