Preheat oven to 350°F / 180°C. Line a baking sheet with parchment paper.
In a medium bowl combine the flour, baking soda and salt. Set aside.
In a mixer bowl fitted with the paddle attachment, beat the peanut butter, butter, granulated sugar and brown sugar until light and fluffy. Add in the egg and vanilla. Scrape down the sides and bottom of the bowl as needed. Add in the flour mixture on low speed until just combined. Do not over mix.
Add some granulated sugar into a small ball. Using the cookie scoop, scoop the dough out into balls and roll them in the granulated sugar before dropping them onto prepared baking sheet. Make sure to leave 2-inches space between them for spreading. I like to sprinkle the tops of the dough with extra sea salt but it’s optional. Bake at 350°F for 10-12 minutes, until cookies are slightly puffed up and begin to brown at the edges. Allow cookies to cool on the baking sheets for 10 minutes then gently transfer to a wire rack to cool completely.
Store cookies in an airtight container for up to 3 days. The leftovers can be frozen for up to 2 months.