In a low-sided heavy-bottomed pan, pour in granulated sugar and place it over low heat. Gently swirl the pan until the sugar begins to melt.

Add unsalted butter, heavy cream, and kosher salt to the melted sugar, whisking until smooth, then set aside.

In a medium bowl, whisk together all-purpose flour, cocoa powder, baking soda, kosher salt, and espresso powder until well combined.

In a stand mixer, cream together unsalted butter, granulated sugar, and brown sugar until light and fluffy.

Add the large eggs one at a time, mixing well after each addition, then add vanilla extract.

Gradually add the dry ingredients to the wet mixture and gently fold in dark chocolate chips.

Using a cookie scoop, portion the dough into balls weighing about 2.5 ounces each, create indentations with your thumb, and freeze for 1 hour.

Preheat your oven to 350°F (175°C). Bake the chilled cookie dough for 8-10 minutes until edges are set and centers are slightly soft.

Once cookies are cooled, fill each indentation with caramel, allowing it to ooze slightly, then cool completely before serving.