In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.
In a large bowl, thoroughly mix the peanut butter, maple syrup, butter, egg and vanilla (handheld electric mixer or stand mixer is recommended). Mix until almost smooth; some small butter chunks may remain in the batter, which is okay.
Turn the mixer down to low and slowly add the dry flour mixture until well-combined. Do not overmix. Carefully fold in the peanuts.
Drop the cookie dough by the spoonful onto a large ungreased baking sheet and bake until the cookies are light golden brown, about 13-15 minutes. Transfer to a rack to cool.
Recipe by Tone and Tighten at https://tone-and-tighten.com/healthier-peanut-butter-cookies.html