1-Preheat your oven: Start by preheating your oven to 350°F (175°C) and lining your baking sheets with parchment paper this little step keeps everything from sticking and makes cleanup a breeze.

2-Mix dry ingredients: In a bowl, mix your dry ingredients like flour, cornstarch, baking soda, and salt to ensure they’re evenly distributed for that ideal cookie texture.

3-Cream butter and sugars: Next, cream the softened butter with brown sugar and granulated sugar until it’s light and fluffy, which takes about 3 minutes trust me, this is where the dough gets its amazing chew. Beat in the egg and vanilla extract to create a smooth base that ties everything together.

4-Combine dough and chocolate chips: Once your dough is ready, gently stir in the dry mix until just combined, then fold in the bittersweet chocolate chips.

5-Prepare brownie squares: For the brownie part, bake the boxed brownie mix in an 8×8 pan according to the package, let it cool, and cut it into 25 small squares.

6-Form stuffed cookies: Now, scoop 1.5 tablespoons of dough, flatten it into a thick pancake, place a brownie square in the center, and cover it with another 1.5 tablespoons of flattened dough. Pinch the edges together and flatten to about 3/4 inch thick.

7-Chill the stuffed cookies: Place your stuffed cookies on the prepared sheets, cover with plastic wrap, and chill in the fridge for at least 1 hour to help them hold their shape.

8-Bake cookies: Finally, bake at 350°F for 15 minutes they’ll be slightly undercooked but will set as they cool.

9-Cool and serve: Cool the cookies slightly before serving, and voilà you’ve got gooey perfection!