Preheat the oven to 375°F, then spray a jelly roll pan with non-stick spray and set aside. The sheet pan measures 13x10 inches. (see notes for different sizes)
Combine flour, baking soda, and salt in a small bowl.
Mix the softened butter, granulated sugar, brown sugar, and vanilla extract in a large mixer bowl until creamy. Add eggs one at a time, beating well after each addition.
1 cup unsalted butter, 3/4 cup granulated sugar, 3/4 cup packed brown sugar, 2 teaspoon vanilla extract, 2 large eggs
Mix in the flour mixture. Stir in 1 & 2/3 cups of chocolate and (1 cup of nuts if using) then press into the prepared pan. Top with the 1/3 cup chocolate chips.
2 cups Nestlé Toll House Semi-Sweet Chocolate Morsels, 1 cup chopped nuts
Bake for 15-20 minutes or until golden brown. Cool in pan on wire rack. Cut into bars.
Notes
Pan options:Use a 15x10 jelly roll pan for thinner bars (15-20 min) or a 9x13 pan for thicker bars (22-25 min).For half the recipe, use an 8x8 pan (18-19 min).Do not overbake, pull when center looks barely set.