Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper to prevent sticking.

In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar using a whisk or electric mixer until the mixture is light and fluffy. This process incorporates air into the batter, which helps the cookies rise.

Add the eggs one at a time, mixing well after each addition. Then stir in the vanilla extract.

In a separate bowl, whisk together the sifted flour, baking soda, and salt. Gradually add this dry mixture to the wet ingredients, mixing until just combined. Be careful not to overmix, as this can make the cookies tough.

Fold in the diced apples and chopped walnuts (if using) gently with a spatula until evenly distributed.

Using a cookie scoop or tablespoon, drop rounded balls of dough onto the prepared baking sheet, spacing them about 2 inches apart.

Bake in the preheated oven for 12-15 minutes, or until the edges are lightly golden. The centers may look slightly underbaked, but they will continue to cook on the baking sheet after being removed from the oven.

Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a cooling rack to cool completely.

In a medium saucepan over medium heat, combine the granulated sugar and cook, stirring constantly until it melts and turns a golden amber color. This process is known as caramelization.

Once the sugar is melted, carefully add the butter and stir until melted and combined. Be cautious, as the mixture will bubble vigorously.

Remove from heat and slowly add the heavy cream, whisking constantly until smooth. Stir in the vanilla extract. Allow the caramel to cool slightly before drizzling over the cookies.

Drizzle the warm caramel sauce over the cooled cookies just before serving. Enjoy your delicious caramel apple cookies!