Preheat the over to 350 degrees F. Butter a 9 x 13″ baking dish.
Place the apples in a large mixing bow. Stir in the lemon juice. Mix the vanilla, stevia leaf or stevia extract, flour, peanut butter (if using), cinnamon, and salt into the apples.
Pour the fruit juice into the bottom of the dish. Spoon in the apple mixture.
Mix the oats, chopped nuts and seeds, stevia extract, and stevia concentrate together in a bowl. Sprinkle and stir in the oil. Spread the topping over the apples so it is evenly distributed.
Bake for 50 minutes to 1 hour. If the topping gets done before the apples, cover pan with foil the last 15 minutes of baking.
Option: Topping substitute: 1 ½ cups of granola. Mix ½ cup of the granola into the apples, and spread the rest on top. No need to add stevia sweetener or oil from topping recipe above – granola already has sweetener and oil.