Peel and chop tart apple. Beat eggs with vanilla and oil. Add sugar, flour and salt. Mixture will be stiff. Work in apples and walnuts with your hands. Spread in 9x13 pan and bake at 350f, one hour.
Icing: 1 stick butter, 1 cup brown sugar, 1/4 cup milk. Boil 2-1/2 minutes and spread on cooked cake while it's still hot.