Preheat oven to 350 F. Line a cookie sheets with parchement paper.
Place melted butter and sugars together in a small mixing bowl and stir until combined.
Add egg yolk and vanilla and stir until smooth. Then add peanut butter and mix again.
Slowly mix in dry ingredients, being careful not to over mix.
Using a large cookie scoop, (I use a 4 TBSP) scoop dough into balls and place on a large cookie sheet.
Roll cookie dough balls in granulated sugar. Sprinkle a little salt on too if you like that.
Bake for 10-12 minutes, or until edges are slightly golden brown. Let cool on the cookie sheet for 5-10 minutes to help the center finish setting.
Notes
If you want to add chocolate, ⅓ cup would be the perfect amount!These cookies can be stored in an airtight container for 2-3 days, or months in the freezer.I like to sprinkle extra sugar on top of the cookies after they bake for an extra pretty look. And if you know me, always a little salt too!I have given both cups and grams as measurements. Grams will be more precise, especially when measuring flour. If you don’t have a kitchen scale, no problem! Just lightly spoon flour into your measuring cup to insure its not packed in there. Light and fluffy is the key.