Ingredients :
- 1 cup cold unsalted butter, cubed
- 1 cup granulated sugar
- 1 cup light brown sugar
- 2 large eggs
- 1 teaspoon vanilla extract
- 3 cups all-purpose flour
- 1 teaspoon baking powder
- 1/4 teaspoon baking soda
- 1/2 teaspoon salt
- 2 cups semi-sweet chocolate chips
- 1 cup chopped walnuts (optional)