In a large mixing bowl, beat the butter with granulated sugar and brown sugar until light and fluffy, about 3-5 minutes. Add vanilla extract and egg, mixing until fully incorporated.

In a separate bowl, whisk together all-purpose flour, baking soda, salt, cinnamon, and nutmeg. Gradually add this dry mixture to the wet ingredients, mixing until just combined.

Gently fold in diced apples until evenly distributed.

Cover the bowl with plastic wrap and refrigerate the dough for about 30 to 60 minutes.

Preheat the oven to 350°F (175°C). Line baking sheets with parchment paper.

Drop rounded tablespoons of dough onto baking sheets, spacing them 2 inches apart. Bake for 10-12 minutes until edges are golden and centers remain soft.

Allow cookies to cool for about 5 minutes before transferring to a wire rack. Drizzle with salted caramel sauce and sprinkle with flaky sea salt.