In a low-sided pan, add granulated sugar and melt it over low heat without stirring, swirling the pan gently until it turns a rich amber color, about 10 minutes. Once melted, quickly add the unsalted butter and whisk until fully incorporated. Slowly pour in the heavy cream while whisking continuously until the mixture is smooth. Set the warm caramel aside to cool slightly.

In a large mixing bowl, whisk together the all-purpose flour, Dutch process cocoa powder, baking soda, espresso powder, and kosher salt. In a stand mixer, beat together the unsalted butter, brown sugar, and granulated sugar until fluffy, about 3 minutes. Add the eggs and vanilla extract, mixing until well combined, then gradually incorporate the dry ingredients. Finally, fold in the dark chocolate chips.

Using a cookie scoop or a tablespoon, scoop out 2½ oz portions of the cookie dough and place them onto a parchment-lined baking tray, spacing them about 2 inches apart. Create an indentation in the center of each dough ball to hold the caramel later.

In a mixing bowl, beat the egg whites until frothy. Dip each cookie in the egg whites, coating the top, then roll them in finely chopped pecans. Place the tray in the freezer for 1 hour to firm up the cookies.

Preheat your oven to 350°F (175°C). Bake the frozen Turtle Cookies for 8-10 minutes, or until slightly set but still soft in the center. Allow to cool on the tray for about 5 minutes before transferring to a wire rack.

After the cookies have cooled slightly, fill each indentation with the warm homemade caramel. Let the cookies cool completely at room temperature.