Preheat the oven to 375º Fahrenheit. (If you'd like a cookie with lighter edges, bake at 350º for 10 minutes.) Cover light colored baking sheets with non-stick silicone mats.
In a large bowl, melt the butter. You don't want it super hot and boiling. Just melt it mostly and then stir until any leftover butter chunks melt in. (See image above.)
Add the brown sugar and egg. Mix well until they are both incorporated into the butter and the mixture is smooth and even.
Add the heavy cream and vanilla. Mix again.
Add the flour (Measure it carefully! Do not pack it into the cup), cornstarch, baking soda and salt. Mix just until combined.
Fold in the chocolate chips.
Scoop cookies with a 1 1/4" cookie scoop onto prepared cookie sheets. The dough balls will be about the size of golf balls. The cookies will spread slightly so don't pack them too close.
Press the extra semi-sweet chocolate chips in the tops of the cookies. This gives them a pretty look. (I don't recommend using dark chocolate chips for this because they melt too quickly).
Bake for 9-10 minutes until the edges are set. The browner the cookies are, the crispier they will be. We let them get just barely browned on the edges.
Sprinkle the tops of the cookies with sea salt right as they come out of the oven. This is optional.
Allow to cool a few minutes on the pan before transferring to a cooling rack.
Store in an airtight container at room temperature for up to 3 days. Then freeze any leftovers.
There is no need to refrigerate this cookie dough. Just leave the dough at room temperature, even while the other cookies are baking.*We like these cookies the way the recipe is written. Some say they aren't sweet enough. If you'd like, you can add 1/4 cup of granulated white sugar along with the brown sugar. This will make the cookies sweeter and they will also flatten a little more during baking.**The heavy cream helps keep the cookies soft by adding a little fat. If you don't have any heavy cream, you can add one large egg yolk instead. It's important to only use the yolk if you choose this method.***Don't pack the flour into the measuring cup! This will make your cookies dry. If you aren't weighing the ingredients, take the time to spoon the flour into the cup lightly and then level it off with a knife.****We think this amount of salt is perfect along with the salted butter. If you are extra sensitive to salt, you could leave this out, especially if you are sprinkling sea salt on top of the cookies.The calories shown are based on the recipe making 24 cookies, with 1 serving being 1 cookie. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information.**