- 1 1/4 cups butter (left out to warm for 30 minutes) plus more for greasing pan
- 3/4 cup sugar
- 1 1/4 cup brown sugar
- 1 Tbsp vanilla
- 3/4 tsp salt
- 2 eggs
- 2 egg yolks
- 3/4 tsp baking soda
- 3 cups all-purpose flour
- 2 1/2 cups semi-sweet chocolate chips
- Preheat oven to 350 degrees. Grease a 9″x13″ glass pan with butter.
- In a small saucepan cook 1 cup butter, until brown and nutty smelling. Swirl pan as needed to even brown the butter. You have to keep an eye on it so it doesn’t burn.
- Add the melted butter to a mixing bowl and add remaining 1/4 cup butter cut into 1 tablespoon sized pieces. Mix until butter is melted.
- Add both sugars, vanilla, and salt. Using a whisk attachment beat until blended.
- Beat together eggs, and egg yolks.
- Slowly pour egg mixture into sugar mixture. Beat on high speed for 30 seconds.
- Allow mixture to rest for 3 minutes. Repeat beating mixture for 30 seconds and resting for 3 minutes until mixture becomes thick and pale.
- Add baking soda, and mix for 30 seconds on high. Scrape down the sides of bowl.
- Allow mixture to rest 3 minutes.
- Add flour and mix on low speed until just combined.
- Stir in chocolate chips, and spread evenly in prepared 9 x 13 pan pan. Bake at 350 for 27-30 minutes, or until lightly browned along the edges, but still a little loose in the middle. You can also tell by looking at the bars through the bottom of the pan to see if the middle looks like it cooked.
- Allow cookie bars to cool before slicing and serving.