Pre-heat your oven to 350° and prepare a baking sheet by lining it with parchment paper or a non-stick mat. (See notes about using a stand or hand mixer)
Add the softened butter, white sugar and brown sugar to a mixing bowl (or stand mixer) and beat for about 2 minutes. The mixture will get light and fluffy.
Add in the 2 eggs, and vanilla extract and beat again just until everything is fully combined.
In a separate bowl, whisk together the flour, cornstarch, and baking soda.
Add the flour mixture to the butter/sugar mixture in thirds. It will be VERY thick but it will come together with a little elbow grease! (I like to switch to a wooden spoon to do this)
Add in the chocolate chips and mix again.
Scoop out the dough into roughly the size of a golfball (about 2 tablespoons). Place them on the lined baking sheet.
Bake for 12-14 minutes just until the very edges start to turn a golden color.
Allow to cool on the baking sheet for 5-10 minutes.
Once completely cooled, store in an airtight container with a slice of bread to keep them soft for up to 5 days!