Cut butter into 1 inch slices and melt in a medium saucepan over medium heat. Remove from heat and pour into the bowl of a stand mixer. Allow the butter to cool for 20 minutes while you prepare the dry ingredients. Alternatively, you can melt the butter in the microwave in 30 second intervals.
1 (227 g) cup Unsalted butter
In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
2 ¾ (344 g) cups All purpose flour , 1 teaspoon Baking soda , ½ teaspoon Kosher salt
In the stand mixer bowl with the melted butter, beat the melted butter and both sugars with the paddle attachment until thick and creamy, about 1 minute.(Alternatively you can do this in a large bowl with an electric hand mixer).
1 ¼ (250 g) cup Granulated sugar , ¼ (55g) cup Light brown sugar
Add in the egg, egg yolk, and vanilla extract and mixed until fully combined, scraping the sides of the bowl. About 1 minute.
1 large Egg, 1 large Egg yolk , 1 tablespoon Vanilla extract
Add the flour mixture in 2 additions, mixing until just combined. After adding the second addition of flour, mix until you only see a few streaks. Remove the mixing bowl from the stand mixer and add in the chocolate chips. Using a rubber spatula, fold in the chocolate chips until just combined. Cover bowl with plastic wrap and refrigerate for 2 hours.
2 (12 oz) cups Semi-sweet chocolate chips
Line a large baking sheet with parchment paper and set aside. Preheat the oven to 325 degrees F. Remove the chilled dough from the fridge and scoop the dough by 2 ½ tablespoons. Roll dough into tall cookie dough balls. If you have a kitchen scale, the dough balls should weigh 1.7 oz or 47 g. Roll balls in sugar to coat. If your kitchen is warm and your cookie dough balls become wet and sticky, place them in the fridge for 10 minutes to harden. Place 4 balls of dough onto the prepared baking sheet, about two inches apart.
Bake cookies for 12 - 14 minutes depending on the texture of cookie you like. 12 minutes will yield a soft, gooey cookie while 14 minutes will give you a firmer cookie (don't worry it will still be soft). The cookies are ready when they are a light golden brown on the edge but pale and slightly wet in the middle. The cookies are better when they are slightly underbaked and will harden as they cool.
Remove the cookies from the oven and firmly tap the baking sheet ( about 5 times) on a heatproof surface to deflate the cookies. Top cookies with extra chocolate chips if desired. Allow cookies to cool on the baking sheet for 10 minutes then transfer to a cooling rack to cool completely. They will be very soft so be sure to allow them to cool completely. I know its hard!! Enjoy!!