To a large, microwave-safe bowl add the butter and heat on high power to melt, about 1 minute. Wait momentarily before adding the egg so you don’t scramble it.

Add the eggs, sugars, vanilla, and whisk to combine.

Add flour, cornstarch (keeps cookies soft) baking soda, salt, and stir to combine. Dough may seem crumbly yet oily, this is okay.

Add the chocolate chips and stir to combine.

Using a large cookie scoop, ¼-cup measure, or your hands, form approximately 11 equal-sized mounds of dough, roll into balls, and flatten about halfway. Tip – Strategically place a few chocolate chips that are likely at the bottom of the mixing bowl and don’t want to incorporate onto the top of each mound of dough, and add more as necessary for a nice visual pop of chocolate.

Place mounds on a large plate or tray, cover with plasticwrap, and refrigerate for at least 4 hours, up to 5 days. Do not bake with unchilled dough because cookies will bake thinner, flatter, and be more prone to spreading.

Preheat oven to 350F, line a baking sheet with a Silpat or spray with cooking spray. Place dough mounds on baking sheet, spaced at least 2 inches apart (I use a half-sheet pan and bake 8 cookies per sheet) and bake for about 12 to 14 minutes (if your cookies are smaller than mine, reduce baking time) or until edges have set and tops are just set, even if slightly undercooked, pale, and glossy in the center; don’t overbake. Cookies firm up as they cool. Allow cookies to cool on baking sheet for about 10 minutes before serving. I let them cool on the baking sheet and don’t use a rack.