This cookie dough requires at least 3 hours of chilling, but overnight is preferred for easier handling.

In a large bowl, beat the butter, granulated sugar, and brown sugar on medium-high speed for about 3 minutes until fluffy and light. Add the egg and vanilla, then beat until combined, scraping the bowl as needed.

In a separate bowl, whisk the flour, cocoa powder, baking soda, and salt. Slowly add the dry ingredients to the wet on low speed until combined. The dough will be thick. Beat in the milk, then the dark chocolate chips on medium-high speed. The dough will be sticky. Cover and chill for at least 3 hours or up to 3 days.

Remove dough from the refrigerator and let sit at room temperature for 10 minutes. Preheat oven to 350°F (177°C). Line baking sheets with parchment paper.

Scoop 2 Tablespoons (40g) of dough, divide in half, and roll each half into a ball. Make a thumb indent in one ball, place a caramel candy in the center, then top with the other dough ball and seal. Repeat for all cookies.

Arrange stuffed cookie dough balls 2

Bake for 10-12 minutes, or until edges are set and centers are still soft. Let cool on baking sheets for a few minutes before transferring to a wire rack to cool completely.