• Preheat the oven to 325° F. Line a 14x17 sheet pan with parchment paper, letting it hang over both sides. Set aside.

For the Brownie Layer:

• Use a hand mixer to beat the melted butter and granulated sugar in a large bowl until smooth. Add the eggs and vanilla, whisking to combine. Then, stir in the oil and cocoa powder just until smooth.
• Using a rubber spatula, stir in the flour, cornstarch, baking soda, and salt just until combined. Gently fold in the chocolate chips.
• Pour the batter into the prepared sheet pan, smoothing it out evenly. Set aside.

For the Cookie Layer:

• Sift the flour, baking soda, and salt in a medium-sized bowl.
• In a separate large bowl, mix the brown butter, brown sugar, and granultaed sugar until well combined. Add the eggs 1 at a time, beating for 1-2 minutes to combine. Then, add the vanilla extract, and beat for another 1-2 minutes or until smooth.
• Slowly add the dry ingredients to the bowl of wet ingredients, mixing just until they’re combined. Be careful not to overmix!
• Fold in the chocolate chips.
• Crumble the cookie dough evenly over the brownie batter, covering it completely.
• Bake 30-35 minutes or just until the top is bronwed.
• Remove from the oven, sprinkle the Maldon salt on top, and set aside to cool completely. Slice the brownies into bars, and serve!
• Store in an airtight container at room temperature or in the fridge for up to 1 week.