In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
In a large mixing bowl, whisk together the melted butter, brown sugar, and granulated sugar until smooth and glossy.
Add the egg, egg yolk, and vanilla extract. Mix until fully combined and the mixture looks thick and cohesive.
Add the dry ingredients to the wet ingredients. Using a rubber spatula, fold gently just until no dry flour remains. Do not overmix.
Fold in the chocolate chips or chocolate chunks until evenly distributed.
Cover the bowl with plastic wrap and refrigerate the dough for at least 2 hours, or overnight for best flavor and texture.
When ready to bake, preheat the oven to 350°F . Line a baking sheet with parchment paper.
Use a cookie dough scoop to portion the dough into tall balls, about 2 tablespoons of dough each. Space cookies at least 2 to 3 inches apart.
Bake for 9 to 11 minutes, until the edges are set and lightly golden brown while the centers still look soft.
Let the cookies rest on the baking sheet for 10 minutes before transferring to a wire rack to cool completely.