This 30 Minute Blondie Recipe is a classic that will become your family favorite bar cookie! It's filled with chewy buttery goodness and is easy to make in just a few mintues. Melted butter is key for making the chewiest Blondies!
Place rack in middle of oven and preheat oven to 350 degrees.
Line a 9x13 pan with foil or parchment and coat lightly with cooking spray.
Melt butter in a heavy (4 qt pan) on stove top over medium heat. When butter is almost melted, remove from heat and stir until butter melts.
Add sugars to melted butter and stir with spoon until dissolved. Add vanilla.
Add beaten eggs (2 eggs + 1 egg yolk) to butter and sugar mixture. Mix with large spoon until blended.
Add the flour, salt, nuts and/or chips (if using), and cornstarch. Fold into the butter mixture by hand until all flour has disappeared. Make sure to add the extra flour if not using nuts or chips!
Spread mixture over foil or parchment in prepared pan. Bake for 20-25 minutes or until crust forms on top and knife inserted into center of pan comes out clean or with a few moist crumbs attached. The mixture should not coat the knife. Do not over bake!
Remove from oven, cool completely and remove foil or parchment from pan and cut when cooled.