Preheat the oven to 350.

Line two half sheet pans with parchment paper and set aside.

Beat together the peanut butter, brown sugar and granulated sugar until well combined with a wooden spoon in a large bowl.

Add the egg, baking soda, vanilla and salt and beat until well combined.

Roll the dough into 1-ounce balls, place 8 per prepared sheet pan, then flatten with the tines of a fork.

Bake for 10 minutes, or until the cookies look dry and are just lightly browned.