In a small bowl, whisk together the flour, baking soda, and salt.
In the microwave or in a small saucepan, melt the butter. Pour the melted butter into a medium-sized mixing bowl. Add in both sugars and whisk until well combined.
Add in the egg and whisk until it is well incorporated. Then, add in the egg yolk and vanilla, whisking until fully incorporated as well.
Add in the flour mixture and chocolate chips. Lightly fold the dough together just until no flour streaks remain.
Cover the dough and let rest in the fridge for at least 30 minutes, up to overnight.
Preheat the oven to 350°F / 175°C. Line a cookie sheet with parchment paper or a silicone baking mat.
Use a 3 tbsp. cookie scoop to dish out the cookies, leaving at least 2" between each cookie to allow room for spreading. Bake for 12 minutes or until the edges are golden brown.
Leave the cookies to continue baking on the cookie sheet for an additional 5 minutes before transferring to a wire rack to cool. Serve and enjoy!
Notes
These cookies will keep well in an airtight container at room temperature for up to 3 days.