In a large bowl sift together 2 1/2 cups flour, 1 teaspoon baking soda, and 1 1/2 tsp salt.
In a separate bowl add 1 cup of melted unsalted butter, 1 cup of granulated sugar, and 1 1/4 cup of golden brown sugar. Using a whisk, mix it all together for about 1 minute. You want to make sure the sugar and butter are well incorporated together.
Now add 1 egg, 1 egg yolk, and 1 1/2 teaspoons of vanilla extract to the butter and sugar mixture. Whisk again thoroughly.
Now add the flour mixture to the cookie batter and mix together using a spatula.
Reserve 1/3 cup of semi-sweet chocolate chips from 2 cups before adding them to the cookie dough. Mix them in thoroughly.
Now line a 9x13-inch deep baking dish with parchment paper and press in the cookie dough. Now top it with the remaining 1/3 cup of semi-sweet chocolate chips and bake at 350°F for 25-30 minutes on the center rack or until the center is baked through. Every oven is different so the bake time may vary.