Preheat oven to 350 degrees.
Microwave the butter for about 30 seconds to just barely melt it.
Mix butter and sugars until smooth and creamy, using a mixer.
Add vanilla and the egg until just incorporated, usually about 10 seconds (do not over mix, the cookies will be stiff).
Add flour, baking soda, salt. Mix until crumbles form and add chocolate chips!
Roll the dough into 12 large balls and place on a cookie sheet. Bake for 10 minutes. Do not overbake. Take them out even if they look like they’re not done yet. They will be pale and puffy.
Let the cookies cool for 30 minutes.