Mix first 5 ingrediants, add remaining ingredients and beat well. Pour into greased Jelly Roll Pan (I usually just use a 9/13 glass cake pan). Bake at 350 deg for 15-20 minutes.
Beat together 1 cup powdered sugar and all remaining ingredients for 5min. Add 1-3 cups more powdered sugar (a little at a time until you get the consistency you want) and beat well. Spread onto cooled cake layer. Put in freezer while you make the frosting.
Boil together sugar, margarine, and milk for 1 1/2 minutes. Remove from heat and add chocolate chips and vanilla. Beat until cooled and slightly thickened. Spread over filling layer and let stand until frosting cools and sets.