1. Preheat oven to 350 degrees. Line two baking sheets with parchment paper.

2. In a medium bowl, combine brown sugar, eggs, and vanilla and whisk to combine. 

3. Add peanut butter and mix until incorporated. Continue to mix until the dough is very, very thick and holds its shape when scooped. 

4. Using a tablespoon or small cookie scoop, drop tablespoons of round dough onto the prepared cookie sheets, leaving an inch or so between each (they don’t spread much). Sprinkle each dough ball with a generous pinch of flaky sea salt. 

5. Bake cookies, one batch at a time, for 14-17 minutes, until they are just barely beginning to brown around the edges. Err on the side of underdone to ensure a moist, chewy center. 

Allow cookies to cool on the baking sheet for a few minutes until they’re set, then transfer to a cooling rack. Store in an airtight container.