01 -
Preheat the oven to 350°F. Lightly grease a 9x13-inch baking dish to prevent sticking.
02 -
Prepare the brownie batter following the package directions. Pour the batter into the greased baking dish and bake for 20 minutes.
03 -
In a medium bowl, whisk together granulated sugar, corn syrup, eggs, melted unsalted butter, and vanilla extract until the mixture is smooth. Fold in pecans until evenly distributed.
04 -
Remove the partially baked brownies from the oven. Pour the pecan mixture evenly over the brownie layer, then return to the oven and bake for an additional 25 to 35 minutes, until the topping is set but with a slight jiggle in the center.
05 -
Allow the brownies to cool completely at room temperature before slicing into approximately 20 squares.