Preheat your oven to 325-F and spray a 9x13-inch baking dish with nonstick cooking spray, then line it with parchment paper; set it aside.
Toast the chopped pecans in a dry skillet over medium heat until they're fragrant and slightly darker in color. Set aside to cool.
Melt the butter in a microwave-safe bowl until just bubbling, then add the chocolate chips and stir to melt. Pop it back into the microwave for 15-20 seconds if needed, to fully melt the chocolate. Set aside to cool.
Whisk together the brown sugar and white sugar. Then, add the eggs and vanilla. Mix well to combine, scraping down the sides as needed.
Addthe melted chocolate to the sugar-egg mixture and mix well, then add the cocoa powder and flour and stir well to combine.
Transfer the brownie batter to the prepared baking dish and bake at 325-F for about 30 minutes or until starting to set around the sides and top.
While the brownies are baking, mix the remaining 1 cup of brown sugar, 2 eggs, vanilla extract, and butter until well combined. Stir in the toasted nuts and mix well.
Spread the pecan pie topping on the brownies and return them to the oven for 20-25 minutes or until the topping is set in the middle and starting to bubble around the sides.
Cool the brownies in the pan on a wire rack before cutting them into squares.
Notes
Chef Jenn's Recipe Notes
Use quality chocolate chips for a richer flavor. Or, use dark chocolate chips for an even darker chocolate flavor.
Don't overmix the batter to keep the brownies fudgy.
Allow the brownies to cool completely in the pan for cleaner cuts. Or, partially freeze the brownies, and your cuts will be perfect.