Wash and peel apples.
Cut the apples into thin slices and put them in a baking pan, spreading them evenly and compactly.
Put the water with lemon and sugar on all the apples to prevent them from darkening.
In a separate bowl, mix oats, 3 Tbs sugar, coconut, ground nuts, vanilla, oil, cinnamon, and salt.
Mix until all ingredients are well incorporated.
Spoon mixture over apples.
Bake for 45 minutes at 340º C.