Heat oven to 350 degrees F. Butter two 8-inch cake pans and dust with flour.
Using an electric mixer, mix shortening and sugar together until they are
creamy, smooth and light.
Add eggs one at a time and beat well after adding each one.
In a separate small bowl, make a paste of the red food coloring and cocoa.
Add the cocoa paste to the egg mixture.
Mix flour and salt together. Mix buttermilk and vanilla extract together.
Add the dry ingredients to the egg mixture alternately with the buttermilk
mixture. Beat for 2 minutes after all ingredients have been added.
Mix in the vinegar and baking soda.
Pour into the prepared cake pans and bake for about 35 minutes or until
the cakes pull away from the sides of the pans slightly.
Turn the cakes out onto cooling racks and cool completely.
Split each layer in half. Take a length of unflavored dental floss and loop
it around the layer. Cross the two ends and pull. As you tighten the floss,
it will gently cut through the layer and you will have two even halves.