Preheat oven to 350°F. Mix butter and sugars until fluffy, and light colored. Add egg and vanilla and blend.

Sift together flour, cornstarch, baking soda, and salt. Add to the butter mixture. Stir in chocolate chips.

Roll balls of dough and plop on a cookie sheet. Bake for 8-10 minutes until barely golden brown around the edges. Don't cook longer than 10 minutes or the cookies won't be chewy.

Let them cool and enjoy!