In a large bowl, using a hand-held mixer or stand mixer with paddle attachment, cream the butter + sugars together on medium speed.
Mix in the peanut butter, egg, + vanilla (in that order).
Slowly mix in the baking soda, flour, + salt, taking care not to not overmix.
Fold in the chocolate chips.
Chill the dough for at least 30 minutes.
Preheat oven to 350 degrees.
Drop chilled dough by heaping tablespoonfuls onto a parchment or silpat-lined cookie sheet.
Bake for 8-10 minutes.
Cookies will be soft + may appear not completely done, but they will firm up as they cool.
Allow to cool completely on a wire rack + enjoy!