1teaspoonsea saltplus more for sprinkling the tops
Preheat the oven to 350°F and line a baking sheet with parchment paper. Set aside.
In a stand mixer fit with the paddle attachment, beat the softened butter, peanut butter, white sugar and dark brown sugar together until light and fluffy.
Scrape down the bowl and add the egg, egg yolk and vanilla extract. Mix well.
In a separate bowl mix together the flour, baking soda, and salt. Add the dry ingredients to the wet ingredients and mix until just combined.
Using a cookie scoop, scoop the dough out into 1 inch balls, dropping them 2 inches apart on the prepared cookie sheet. Bake at 350°F for 12 minutes or until the cookies have puffed up and are set on the edges, but are still gooey in the middle. Allow to cool completely before eating!
Cookies can be frozen, prebake for up to 3 months.
Store baked cookies in an airtight container for up to 5 days.