In a large mixing bowl cream together the shortening and sugar.
Add eggs, one at a time, beating well after each addition.
In a small bowl make a paste with the cocoa and red food coloring.
Add the paste to the creamed mixture.
Mix salt, vanilla and buttermilk together.
Add to the creamed mixture alternating with the flour.
Add baking soda and vinegar and fold into the cake batter.
Fill prepared liners about ⅔ full or you can use 2 (9 inch) layer cake pans.
If baking cupcakes bake for 18 minutes and if using cake pans bake for 30 minutes.
Use a toothpick to check is cake is done. The toothpick should not have any liquid batter on it.
Frosting
In a small mixing bowl whisk together the flour and milk to help break up the lumps of flour.
Pour into a saucepan and cook over low-medium heat until a pudding like consistency is achieved. Stir often to keep from scorching.
Remove from heat and allow to cool.
Cream together the butter, shortening, sugar and vanilla.
Add the milk and flour mixture (after it has cooled) and beat until smooth.
Top on cake and refrigerate.
Notes
Allow the milk mixture to cool for about 15-20 minutes. I gently whisked the milk mixture while it was thickening in the pot. I used two 1.oz bottles of red food coloring. I didn't purchase them in a pack.