Preheat your oven to 350°F (175°C).
In a mixing bowl, combine the sliced apples, lemon juice, sugar, cinnamon, and nutmeg. Toss to coat the apples evenly.
Transfer the apple mixture to a baking dish and spread it out evenly.
In another bowl, mix the rolled oats, flour, brown sugar, and melted vegan butter until crumbly.
Sprinkle the oat mixture evenly over the apples.
Bake in the preheated oven for about 45 minutes, or until the topping is golden brown and the apples are tender.
Let it cool slightly before serving. Enjoy!