Preheat your oven to 350°F. Line baking sheets with parchment paper. This is crucial for easy cleanup and preventing sticking.
In a large bowl, cream together the room temperature unsalted butter, light brown sugar, and granulated sugar until light and fluffy.
Beat in the egg and vanilla extract until fully incorporated. The mixture should look creamy.
In a separate medium bowl, whisk together the all-purpose flour, salt, and cornstarch. Make sure there are no lumps.
Gradually add the dry ingredients to the wet ingredients, mixing on low speed. Be careful not to overmix! Overmixing can lead to tough cookies.
Gently fold in the milk chocolate chips until they're evenly distributed throughout the dough
For those truly bakery-sized cookies, use a 2 ounce scooper (aiming for about 4.5 ounces of dough per cookie). You might need to slightly mound the scoop for that exact weight, or use a kitchen scale for precision. Place the generously sized dough balls onto your prepared baking sheet, leaving at least 2-3 inches between each cookie. You'll likely only fit 4-6 cookies per standard baking sheet.
Bake for 17-18 minutes, or until the edges are golden brown and the centers are still soft and slightly underbaked. Larger cookies will take a bit longer to cook through while remaining chewy
Let the cookies cool on the baking sheet for 10-15 minutes before transferring them to a wire rack to cool completely. These big cookies need extra time to set up properly.
Notes
Nutritional values may vary and are meant to be a guide.