Caramelize 1 cup of sugar by stirring constantly in a heavy pan over low heat until liquefied and golden brown.
Slowly stir in hot milk; cooking over low heat until smooth, stirring constantly.
Measure mixture – should be 1-3/4 cups. Add more milk if necessary; cool thoroughly.
Sift flour, baking powder and salt together.
Cream shortening; gradually add remaining 1 cup sugar, and cream until light and fluffy.
Add unbeaten eggs, one at a time, beating thoroughly after each addition.
Add dry ingredients alternately with caramel milk, stirring only enough after each addition to blend thoroughly. Do not beat.
Pour into two greased 9-inch or three 8-inch layer pans.
Bake at 375 degrees for 25-30 minutes. When done, cool completely.
To make icing, melt butter in a large saucepan and add brown sugar.
Bring mixture to a boil, stirring frequently, about 1 minute until thickened.
Remove from heat and add milk. Beat with wire whisk until smooth.
Add vanilla and beat again. Add enough powdered sugar until icing is pourable.
Pour a third of icing over the first layer and let sit for 15 minutes.
Place second layer on top and pour remaining frosting over and let sit until icing sets.
(Divide icing in thirds if making three layers.)