Preheat oven to 350 degrees f.
Line a 9x13 baking dish with parchment paper. You want to tear off a 1 1/2 times the pan length to have some overhang to make it easier to pull out brownies & cut them.
Add flour, cornstarch, salt, and baking powder to a stand mixer, and mix on low to combine.
Add melted butter and Domino Golden® Sugar to a stand mixer, and mix until combined.
Add in eggs, yolk, and extract and combine until fully integrated.
Turn off mixer, and remove bowl from machine.
Fold in nuts and chocolate chips with a rubber spatula. Dough with be thick.
Add dough to parchment lined pan and spread it evenly in the pan.
Bake for 25-30 minutes at 350. Use a toothpick at the 25-minute mark to test if the center is done. The blondies should be firm and not jiggly.
Once fully baked, carefully remove them from the oven with mitts, and allow them to cool for 30 minutes before cutting them into 15 pieces.
Enjoy warm.