Prepare the Caramel Sauce: In a medium saucepan over medium heat, melt the butter.

Add granulated sugar and brown sugar. Stir constantly until the sugars dissolve completely.

Pour in the water, and mix well to combine.

Continue to stir for 5-7 minutes, or until the mixture thickens and turns a deep golden brown color.

Sprinkle in the cinnamon and salt. Stir to incorporate, then remove from the heat.

Cook the Apples: In a separate large skillet, cook the sliced apples over medium heat for about 5 minutes, until they begin to soften slightly.

Pour the prepared caramel sauce over the apples and stir gently to coat them evenly.

Simmer the caramel apple pie filling mixture for 10-12 minutes, or until the apples are tender but still hold their shape. Be careful not to overcook them.

Cool and Use: Let the caramel apple pie filling cool completely before using it in a pie or other dessert.