In a stand mixing bowl, cream together the butter, peanut butter, and miso until smooth and combined, about 1 minute.
Mix in the sugars for 2-3 minutes, until light and fluffy.
Mix in the egg and vanilla.
Fold in the dry ingredients until just combined.
Cover and chill the dough in the fridge for 1 hour, or until firm.
Then scoop the dough into 2 tablespoon-sized balls, roll them in cane sugar, and place them onto a parchment-lined baking tray.
Chill the tray in the freezer overnight. This chill time gives the cookies the best flavor! If you need to bake them the same day, chill them for at least 2-3 hours in the freezer before baking.
Then preheat the oven to 350 F/180 C.
Roll the cookies in cane sugar again, leaving a pile of sugar on top of each dough ball. This is crucial for achieving the crackled tops!
Bake the cookies spaced 2-3 inches apart for 10-11 minutes, or until the edges are golden brown and the centers are soft, puffed, and crackled.
Let the tray cool on a wire rack. If desired, you can drizzle them with extra melted peanut butter or enjoy them as is!