Preheat your oven to 325°F.
Grease and flour a bundt pan (this helps the cake pop out nicely).
In a large bowl, mix oil, applesauce, sugar, eggs, vanilla, and cinnamon until fluffy.
Stir in the chopped apples and cinnamon chips.
Add flour, baking soda, and salt. Mix until smooth.
Pour the batter into your prepared bundt pan.
Bake for about 1 hour and 20 minutes. A toothpick should come out clean.
While the cake bakes, make the topping. Combine butter, brown sugar, milk, and cinnamon in a saucepan. Boil for 2 minutes.
When the cake is done, pour the topping over it while warm.
Let it cool 30 minutes before removing from the pan.