Preheat oven to 350℉ and line large baking sheet with parchment paper.
In a bowl, cream together the butter and sugars for 3 minutes using an electric mixer until pale and fluffy. Scrape the edges of the bowl as needed.
½ cup salted butter, ½ cup brown sugar, ½ cup white sugar
Add in the egg and vanilla, mixing well until the egg is all the way mixed in and it turns the mixture fluffy.
1 large egg, 1 teaspoon vanilla extract
Add in salt, baking soda, cornstarch, and flour and mix on low speed until dough forms. Mix for at least 1 minute, it will look crumbly at first but will be more play-dough like in texture the longer it's mixed, which is what we want.
1 teaspoon salt , 1 teaspoon baking soda, 1 Tablespoon cornstarch , 2 cups all purpose flour
Add chocolate chips last, make sure to save a few to put on top of the cookie before baking.
1 cup chocolate chips of preferred flavor
Place the dough on a parchment paper lined baking sheet. Shape into a heart, long and narrow, about 9-10 inches (22-25cm) across and in length. Add a few chocolate chips to the top and use a spatula or knife to press the edges flat and even them up to make them neat. Bake for 15-17 minutes, until edges are beginning to crack and middle no longer looks wet. Let cool completely before frosting.