Recipe can be found in Gourmet, September 1998 (Original recipe from Pasta & Co. in Seattle)
Preheat oven to 300°. Butter (or spray with Pam) a 13 x 9 x 2 inch glass baking dish. Into a large bowl, sift together sugar, baking soda, cinnamon and salt. Add oil, eggs and vanilla and whisk until smooth. Peel and core appes and slice about 1/4 inch thick (should be about 6 cups). Add apples and walnuts to batter and stir until coated. Stir in flour just until combined well and spread batter evenly in baking dish.
Bake cake in middle of oven for 1 hour and 40 minutes, or until a tester comes out clean. Cool completely in baking dish on rack.
We cut the cooled cake into squares and froze in zip loc bags. To serve, let sit at room temperature for 20-30 minutes. Two other comments - this sounded like a lot of sugar, but it "works". Also the cooking time seemed long, but that, too, is correct.