Preheat your oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish.
In a large bowl, combine apples, granulated sugar, brown sugar, flour, cinnamon, nutmeg, lemon juice, and vanilla extract. Toss until evenly coated.
Spread the apple mixture evenly into the prepared baking dish.
In a separate bowl, mix oats, flour, brown sugar, melted butter, cinnamon, and salt until crumbly.
Sprinkle the topping evenly over the apples.
Bake for 40–45 minutes, until the topping is golden brown and apples are tender.
Allow the apple crisp to cool for at least 10 minutes before serving.