Preheat oven to 325F. Grease or parchment-line a 9×13-inch metal pan. Set aside.
In a large saucepan, combine butter, sugars, and water. Bring to a boil, stirring regularly.
Remove pan from heat.
Whisk in 1 ¾ cups chocolate chips until melted and well-combined.
Add eggs and vanilla. Whisk until well-combined.
Add flour, salt, and baking soda. Whisk in just until combined. Don’t overmix.
Stir in the remaining 1 cup chocolate chips and 20 of the Oreo cookies until combined.
Pour the batter into the prepared pan, smoothing as needed.
Gently press the remaining 20 Oreo cookies into the top of the batter.
Bake for about 30-40 minutes, or until a toothpick inserted in the center comes out with a few fudgy crumbs.
Let the brownies cool to room temperature before cutting and serving.
Notes
Butter: I use salted butter in this recipe. If using unsalted butter, increase the salt to 3/4 teaspoon.
Brown sugar: I use light brown sugar in this recipe.
Chocolate chips: Bittersweet chocolate chips are 60% cacao. A good substitute would be dark chocolate chips. If you prefer, you can use semisweet chocolate chips. However, the brownies will be sweeter.
All-purpose flour: It’s important to use a light hand when measuring flour for brownies. To get the proper amount of flour, weigh the flour or sift or stir the flour. Lightly spoon into the measuring cup and level.
Oreos: I used original Oreo cookies in this recipe. Feel free to use a different flavor if you prefer.