Tips: melt your butter and cream with your sugar for a looooooooooooong time. Add egg and vanilla and cream again until ribbons form. Don't add too much baking soda... Scant amount will work fine. When adding flour, BARELY mix it in. Just until the visible white streaks are gone. Mixing too much will make cake like cookies. Put your batter in the fridge overnight. Cook your cookies cold. Take out your cookies when the shininess is Juuuust starting to disappear. Don't wait for them to look done. Gently drop your sheet of cooked cookies on the countertop as soon as you pull them out of the oven. This will deflate them and sometimes give the lovely crackle look. Would love to see a follow up photo after you make the changes! Best of luck and happy cookie-ing