Preheat your oven to 350F.
In a bowl, mix oats, flour, melted and sugar. Mix with a spoon until a crumble is formed. Keep aside.
In a bowl, add chopped apples, cinnamon, lemon juice, vanilla extract & sugar. Mix until the apples are fully coated with cinnamon, sugar and vanilla.
Add your apple mixture to a ramkein and then top with your crumble.
Bake for 15 minutes and let them cool for 5 minutes.