White Chocolate Chip Cookies

In a large bowl, cream together the butter, brown sugar and white sugar until light and fluffy. Add the egg and vanilla and beat until smooth. Slowly add in the flour, cornstarch and baking soda, making sure it is well incorporated. Add the white chocolate chips and stir to mix throughout the dough. Cover tightly and chill for at least 30 minutes, up to 24 hours.
When ready to bake, reheat oven to 350 degrees F. Line a baking sheet with parchment paper or a silicone mat.
Scoop out 2-tablespoon portions and roll into balls, then shape balls so that they are slightly taller than wide. Place each ball on the prepared baking sheet, at 1 1/2 to 2 inches apart. Bake for 11 to 12 minutes. Remove from the oven when the starting to very lightly brown.
Sprinkle lightly with salt, if using, as soon as they're out of the oven. Let the cookies cool for 10 minutes on the tray and then transfer to a wire cooling rack.