Prepare your workspace. Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper. The parchment is essential as the caramel can stick to unlined pans.
Mix the dry ingredients. In a medium bowl, whisk together the flour, baking soda, salt, cinnamon, nutmeg, and allspice until well combined and no lumps remain.
Cream the butter and sugars. In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar together until light and fluffy, about 2-3 minutes. The mixture should be noticeably lighter in both color and texture.
Add the wet ingredients. Beat in the egg and vanilla extract until fully incorporated, scraping down the sides of the bowl as needed to ensure everything is well mixed.
Combine wet and dry mixtures. Gradually add the flour mixture to the butter mixture, mixing on low speed just until combined. Overmixing will result in tough cookies, so stop as soon as no dry flour is visible.
Fold in the add-ins. Gently fold in the diced apples, caramel bits, and nuts (if using) with a spatula until evenly distributed throughout the dough.
Shape the cookies. Using a medium cookie scoop or tablespoon, drop rounded portions of dough onto the prepared baking sheets, spacing them about 2 inches apart as they will spread during baking.
Bake to perfection. Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden but the centers still look slightly underbaked. The cookies will continue cooking on the hot baking sheet.
Cool properly. Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely. This crucial step prevents them from breaking apart.
Add the finishing touch. Once cookies are completely cooled, drizzle with warmed caramel sauce in a zigzag pattern. Allow the caramel to set slightly before serving or storing.