Preheat the oven to 390°F (unless you plan to chill the dough first). In a large mixing bowl, cream together the butter, dark brown sugar, and granulated sugar for at least 4 minutes, scraping down the sides of the bowl as needed to ensure a smooth, fluffy mixture.

Add the egg, egg yolk, and vanilla extract, then continue mixing for another minute. Stir in the caramel sauce until fully incorporated.

Gently fold in the flour, baking powder, baking soda, and salt. If you plan to sprinkle sea salt flakes on top of the cookies, reduce the salt in the dough to ½ teaspoon. For best results and less spreading, chill the dough for at least 30 minutes—though a 24-hour chill yields optimal texture and flavor if you have the time.

For baking, use a light-colored baking sheet if available. Roll the dough into light, even balls and place them on a baking sheet lined with parchment paper. Bake for 8 to 11 minutes, or until the edges are lightly golden. Remove from the oven and allow the cookies to rest on the sheet for a few minutes to set.

Before serving, generously drizzle additional caramel over each cookie. If desired, finish with a sprinkle of sea salt flakes for a sweet and salty touch.