Preheat oven to 350
Melt 2 sticks of butter. While butter is cooling, prepare a 9x13 baking dish by lining it with parchment paper, leaving extra to hang over the sides of the dish.
1 cup butter
Coat parchment with cooking spray
In medium sized mixing bowl, pour cooled, but not cold, melted butter into mixing bowl.
Mix in sugar, eggs, and vanilla.
1 1/2 cups sugar, 3 eggs, 1 Tablespoon vanilla
Add flour and salt.
2 cups all-purpose flour, 1/4 teaspoon salt
Mix until combined.
Pour mixture into prepared dish and spread into an even layer.
Bake until the edges are set, but the middle is soft, approximately 25 minutes. They will be golden brown.
Let cool. Pull bar out of pan by pulling on parchment, and flip onto large plate or cookie sheet.