1. Preheat oven to 350 °F. Toss apples, sugar and salt together, and divide equally among 4 individual oven proof bowls.
2. Combine butter and flour with fingertips until mixture is crumbly and has the texture of oatmeal. Add brown sugar, allowing lumps to remain in mixture, and distribute evenly over apples.
3. Bake for 30 minutes. Serve warm or cold with a scoop of ice cream.