Preheat your oven to 350°F (175°C) and line your 9x13 inch baking pan with parchment paper, leaving some overhang for easy removal later.
In a large mixing bowl, combine the melted butter, granulated sugar, and light brown sugar. Mix until the sugars are well incorporated. Add in the eggs and vanilla extract, stirring until everything is well blended.
In a separate medium mixing bowl, whisk together the baking soda, all-purpose flour, and salt. Gradually add the dry mixture to the wet ingredients, stirring just until combined. Be careful not to overmix.
Gently fold in the mini chocolate chips until they are evenly distributed throughout the cookie dough.
Spread half of the cookie dough into the prepared baking pan, pressing it down to form an even layer.
Place the 24 Oreos evenly on top of the first layer of cookie dough. You can arrange them in rows or however you like for an attractive presentation.
In a small saucepan, combine the sweetened condensed milk and 2 cups of chocolate chips over low heat. Stir continuously until the chocolate chips are completely melted and the mixture is smooth. Pour this chocolate mixture over the Oreos, spreading it out evenly.
Take the remaining cookie dough and drop spoonfuls over the chocolate topping. It doesn’t have to cover completely, as it will spread during baking.
Place the baking pan in the preheated oven and bake for 25-30 minutes or until the edges are golden brown and a toothpick inserted in the center comes out with a few moist crumbs.
Once baked, remove the pan from the oven and allow it to cool completely in the pan. Once cooled, use the parchment overhang to lift the bars out and cut them into squares. Serve and enjoy your Oreo Stuffed Chocolate Chip Cookie Gooey Bars!