Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a medium bowl, whisk together the flour, cocoa powder, baking soda, and salt. Set aside.

In a large bowl, cream the softened butter and granulated sugar together until light and fluffy (2-3 minutes).

Beat in the egg and vanilla extract until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Fold in the chocolate chips.

Using a tablespoon, scoop out a portion of dough and flatten it slightly in your palm.

Place about 1 teaspoon of fudge sauce in the center and fold the dough around it, rolling it into a ball.

Place the cookie dough balls on the prepared baking sheet, spacing them about 2 inches apart.

Bake for 10-12 minutes, or until the edges are set but the centers are still soft.

Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.