Steps
Preheat your oven to 350°F (175°C).
In a small bowl, toss the sliced apple with sugar, cinnamon, and lemon juice until well coated.
Place the apple mixture in a small baking dish.
In another bowl, combine rolled oats, flour, brown sugar, and salt.
Add the cold butter and mix with your fingers until the mixture resembles coarse crumbs.
Sprinkle the oat topping evenly over the apples.
Bake in the preheated oven for 25-30 minutes, or until the apples are tender and the topping is golden brown.
Serve warm with a scoop of vanilla ice cream on top if desired.