1. Preheat the oven to 350°F (175°C). Line an 8x8-inch baking dish with parchment paper.
2. In a large bowl, whisk together the melted coconut oil and egg. Add the brown sugar, flour, baking powder, salt, and vanilla, and mix until well combined.
3. Press about two-thirds of the mixture evenly into the bottom of the prepared baking dish to form the base. Set aside.
4. In a separate bowl, toss the peeled and sliced apples with the flour, brown sugar, cinnamon, and nutmeg until the apples are evenly coated.
5. Spread the apple mixture evenly over the base in the baking dish.
6. To the remaining base mixture, add the rolled oats and mix until combined. Add a bit of water if needed so that the mixture sticks together when pressed between fingers.
7. Crumble this oat mixture over the apples.
8. Bake for 40-50 minutes, or until the top is golden and the apples are tender when pierced with a fork.
9. Let the bars cool in the baking dish before cutting into squares.
10. Drizzle with salted caramel sauce before serving. Enjoy!
