Preheat the oven to 375°F and lightly grease four ramekins or oven-safe cups.
In a bowl, toss the diced apples with 1/4 cup of the caramel sauce, cinnamon, and salt until evenly coated.
Divide the apple mixture among the four prepared cups, pressing it down lightly.
In a separate bowl, stir together the oats, flour, brown sugar, and melted butter until the mixture forms clumps.
Spoon the crumble evenly over the apples in each cup.
Bake for 25 to 30 minutes until the topping is golden and the apples are soft.
Remove from the oven and drizzle the remaining 1/4 cup caramel sauce over the warm cups before serving.