Preheat your oven to 350 degrees Fahrenheit. Prepare 3 rimmed baking sheets with parchment paper. In a small skillet over medium heat, melt the butter. Continue stirring as the butter melts. It will take about 8 minutes for the butter to melt completely and for it to begin to brown at the bottom. It will turn foamy at the edges and begin to smell nutty. Remove it from the heat and immediately pour the butter into a heat-proof glass bowl or measuring cup to remove it from the hot skillet (see Note 2). Allow to slightly cool.
3/4 cup butter
In a large bowl, whisk together the flour, baking soda, baking powder, and salt. 1 1/2 cups all-purpose flour, 1/2 teaspoon baking soda, 1/2 teaspoon baking powder, 1/4 teaspoon salt
In the bowl of a stand mixer fitted with a paddle attachment or in a large bowl with a hand mixer, beat together the butter, brown sugar, and granulated sugar until fully combined, about 1 minute. Add in the egg and egg yolk, one at a time. Then beat in the vanilla until just combined. Scrape down the sides of the mixing bowl and give it one final mix.
3/4 cup brown sugar, 1/4 cup granulated sugar, 1 egg, 1 egg yolk, 1 1/2 teaspoons vanilla extract
Add the flour mixture. Turn on the mixer on low, and beat until the flour just begins to incorporate. Then turn the mixer up high for just a few seconds until the flour is fully incorporated. This will allow you to combine the flour all at once without over-mixing the dough.
Stir in the chocolate chips by hand with a spatula.
1 cup chocolate chips
Optional: Chill the cookie dough for 30 minutes in a refrigerator, covered. This step will result in the thicker cookies you see pictured here. You can skip this step and still get absolutely delicious cookies, but they will spread more.
Using a 1 1/2 tablespoon cookie scoop, scoop the cookies into uniform balls. Place the balls two inches apart and bake for 10 to 14 minutes or until the edges of the cookies begin to turn golden brown. Remove the sheet pan from the oven. Allow the cookies to cool on the baking sheet for 2 minutes before moving to a wire cooling rack with a spatula. Enjoy or allow to cool completely and store in an airtight container for up to 2 weeks. For freezing information, see Note 2.