Preheat the oven to 350°F. Line a rimmed baking sheet with parchment paper.

In a medium bowl, whisk together the light brown sugar and eggs until smooth. Really whisk it, give it at least a solid minute of whisking.

Whisk in the vanilla extract, cinnamon, and salt, then the peanut butter until smooth and completely incorporated; you shouldn’t be able to see any ribbons of peanut butter.

If you’d like to get those pretty striations across the top of the cookies, chill the dough by freezing it in its bowl for 15 minutes before scooping it onto the cookie sheet. If you’re not obsessed with these markings, you can scoop it right away (I'm always in a hurry so usually skip the chilling).

Scoop or spoon the dough into balls onto the lined pan (a #16 or #40 scoop is good, but it's up to you how exact you want to be). If you want a tall final cookie, place the tray back in the freezer for 15 minutes before baking. If you don't care, bake right away.

Sprinkle the dough balls lightly with flaky sea salt, then bake. If you have smaller cookies, it will take probably 13 to 15 minutes, and for larger cookies 18 to 20 minutes. I personally like mine a little underdone. When finished, cookies should be golden at edges.

Once you remove from the oven, they’ll need to set on the sheet for a minute or two before they can be lifted intact to a cooling rack. You really want them to cool all the way before eating (the texture is way better...crisp outside, soft inside).