1. **Prepare the Brownie Filling:**

– Preheat the oven to 350°F (175°C).

– Prepare the brownie mix according to the package instructions.

– Pour the batter into a greased 9×13-inch baking pan and bake as directed.

– Once baked, allow the brownies to cool completely.

– Cut the cooled brownies into 1-inch squares and set aside.

2. **Make the Cookie Dough:**

– In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.

– Add the eggs one at a time, mixing well after each addition.

– Stir in the vanilla extract.

– In a separate bowl, whisk together the flour, baking soda, and salt.

– Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

– Fold in the chocolate chips.

3. **Assemble the Cookies:**

– Scoop about 2 tablespoons of cookie dough and flatten it into a disc.

– Place a brownie square in the center of the disc.

– Scoop another tablespoon of cookie dough, flatten it, and place it over the brownie.

– Seal the edges to encase the brownie completely, rolling gently to form a ball.

– Repeat with the remaining dough and brownie squares.

4. **Bake the Cookies:**

– Preheat the oven to 350°F (175°C) if not already done.

– Place the cookie balls onto a baking sheet lined with parchment paper, spacing them about 2 inches apart.

– Bake for 13–15 minutes, or until the edges are golden brown.

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