cup butter, softened to room temperature
2 teaspoons white vinegar
Preheat oven to 350 degrees. Beat the butter and both sugars until light and fluffy. Add eggs and beat until mixed. Beat in vinegar and vanilla. Mix together the flour, salt, baking soda, and cornstarch in a large bowl. Slowly add to batter and mix just until blended. Stir in chocolate chips by hand until mixed.
Drop dough onto parchment paper lined baking sheet by 1/2 cupfuls. (I use a large 1/2 cup measure ice cream scoop.) Leave about 2 inches in between cookies. Bake 20-25 minutes or until cookies are set and light golden brown around. Cool on baking sheet for 5 minutes before transfer to a wire rack to cool completely. Decrease time for smaller cookies.