- Nonstick cooking spray
- 1 cup butter, softened
- 1 1/2 cups firmly packed brown sugar
- 4 large eggs
- 2 cups all-purpose flour
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 1 cup semisweet chocolate morsels
- One 6.5-ounce box brownie mix
- 1/3 cup vegetable oil
Preheat the oven to 350 degrees F. Line a 13-by-9-inch baking pan with heavy-duty aluminum foil with a 2-inch overhang. Spray with nonstick cooking spray.
In a large bowl, beat the butter and brown sugar at medium-high speed with a mixer until fluffy. Add 2 eggs, beating until well blended. In a medium bowl, combine the flour, baking soda and salt. Gradually add the flour mixture to the butter mixture, beating until the mixture forms a soft dough. Stir in the chocolate morsels.
In another large bowl, combine the brownie mix, oil, 1/4 cup water and remaining 2 eggs, beating until well blended.
Spread the the cookie dough in prepared pan. Pour the brownie mixture over the dough. Using a knife, swirl the mixtures together. Bake until the edges start to pull away from sides of the pan, 40 minutes. Let cool in the pan for 1 hour. Cover and refrigerate for 4 hours. Cut into bars.