1 1/2 cups vegetable oil 
2 cups granulated sugar 
3 eggs 
3 cups all-purpose flour * 
1 teaspoon salt 
2 teaspoons vanilla 
1 1/2 teaspoons baking soda 
3 cups finely chopped tart apples 
1 package (6 ounces) butterscotch chips 
1 1/2 cups chopped walnuts 
Topping 
1 cup brown sugar 
1 stick butter (4 ounces) 
1/4 cup milk 
1 teaspoon vanilla 

Combine oil and sugar; mix well. Stir in eggs then beat until smooth and creamy. Add flour, salt, and soda. Stir in remaining ingredients, blending well. Pour batter into a 10-inch Bundt pan or tube pan; bake at 350° for about 1 hour and 10 minutes, or until a wooden pick or cake tester inserted in center comes out clean. 
Combine topping ingredients in a saucepan; cook for 3 to 5 minutes, until sugar is dissolved and mixture is smooth.