First, preheat oven to 350° Fahrenheit. Line two cupcake pans with paper cupcake liners, then set aside. In a medium bowl, whisk together the flour, salt, baking powder and soda, and cocoa powder, then set aside. In a large bowl, using an electric mixer, beat together the eggs, oil, butter, sugar, and red food coloring until smooth. Add in the vanilla, sour cream, and milk and continue to beat until combined. Add in the whisked dry ingredients and stir together until smooth. Add more red food coloring if you want it deeper red.