1Heat oven to 350°F. Line 9-inch square pan with foil, leaving 2 inches of foil overhanging at 2 opposite sides of pan; spray foil with cooking spray.
2In medium bowl, stir brownie mix, oil, water and 2 of the eggs with spoon until well blended. Spread batter in pan. Bake 25 minutes.
3In large bowl, stir brown sugar, corn syrup, vanilla, melted butter and remaining 2 eggs with whisk. Stir in pecans. Pour over partially baked brownie base.
4Bake 25 to 30 minutes or until topping is set. Cool completely in pan on cooling rack. Refrigerate 2 hours. Use foil to lift from pan. Cut into 4 rows by 4 rows.