Preheat oven to 350 degrees Fahrenheit. Coat a 9"x13" pan with nonstick cooking spray. In the bowl of an electric mixer, combine oil, sugar, eggs, vanilla and red food coloring gel. In a separate bowl, stir together flour, salt, baking soda and baking cocoa.
Add flour mixture and buttermilk, alternating, while mixing. At this point, if you'd like to enhance the red color of the batter, mix in more red food coloring gel until desired color is reached.
Spread mixture into prepared pan and bake for approximately 20 minutes, or just until a toothpick comes out mostly clean. Moist crumbs are ideal.
For the frosting, in the bowl of an electric mixer, cream together all ingredients until creamy and fluffy. Spread over cooled bars. Slice and serve.