Cream shortening, sugar and eggs. Make a paste of food coloring and cocoa. Add to creamed mixture. Add buttermilk alternating with flour and salt. Add vanilla. Add soda to vinegar (foams!!!), Blend in.. Pour into 3 or 4 greased and floured 20 cm cake pans. Bake at 350 24-30 minutes. Split layers fill and frost with the following frosting. FROSTING Add milk to flour slowly, avoid lumps. Cook flour and milk 'til very thick, stirring constantly. COOL!! Cream sugar, butter and vanilla 'til fluffy. Add to cooked mixture. Beat, high speed, 'til very fluffy. Looks and tastes like whipped cream.