Cream sugar, oil, eggs on medium in a large mixing bowl.
Add vinegar, 1/2 to 3/4 of the food coloring & vanilla one at a time.
Slowly blend in 1/3 of the sifted flour medium low speed. Add 1/3 of the buttermilk. Repeat by adding 1/3 of sifted flour and 1/3 cup of buttermilk. Repeat the remainder of the sifted flour and buttermilk. Raise mixing speed to medium and add the remaining ingredients.
Pour batter evenly into 2 greased & floured round cake pans. Bake at 350* for 40-45 minutes. Gas ovens, bake at 325* for 40-45 minutes. Check cake after 35 minutes with a wooden toothpick. If it comes out clean from the middle, the cake is done. Cool cakes on a metal rack for approximately 30 minutes before frosting the cake.
Make sure cream cheese is at room temperature. Blend all ingredients together in a mixing bowl. Mix well on medium speed. The higher the mixing speed, the fluffier the frosting will be. Add finely chopped pecans to the frosted cake if desired.