Preheat oven to 350 degrees Fahrenheit. Prepare a 9 by 13 inch Pyrex baking dish, or a large round 10-inch Pyrex dish Place on a baking sheet, lined with parchment paper, to protect from spillage.

Place apples through the food processor fitted with a slicing attachment creating finely sliced apples. Place in the baking dish. Toss with the sugar and apple juice, then smooth out into a smooth layer. They should totally cover the baking dish quite generously.

In a large bowl, mix the oil and sugar by hand; then add eggs and vanilla. Fold in flour, baking powder, and salt to mix to create a very thick batter.

Sprinkle the cinnamon on top of the apples and pour the batter evenly over apples. Give the pan a few gentle shakes. Place on baking sheet and bake 60 minutes (it varies, depending on how juicy apples are) or until cake is firm and slightly browned on top. Cool slightly before serving.