Cake:
Beat together oil, sugar, eggs, and vanilla (about 3 minutes). Sift together the remaining dry ingredients. Add dry ingredients gradually, beat well after each addition. Stir in apples. Combine nuts with 1 tbsp flour. Stir into batter. Pour into a greased and floured 13x9x2 inch pan or 2 square pans. Bake at 350 degrees F for 60 mins (50 mins for 2 squares) or until toothpick comes out dry. Cool
Topping:
Mix ingredients in a saucepan and boil for 3 minutes - stirring constantly. Pour on top of cake at once.