Place butter, sugar, and brown sugar in a bowl and mix with a hand mixer for about 5 minutes, until the mixture is light and creamy.

Add the peanut butter and miso and mix with a hand mixer (medium speed) for about one minute until combined. Add the egg and vanilla extract and briefly mix with the hand mixer, just until combined with the other ingredients.

In a separate bowl, combine the flour, baking soda, and baking powder. Add ⅓ of the flour mixture to the dough and mix with a hand mixer (lowest speed setting) until just combined. Repeat the process for the remaining flour in two more additions. You shouldn't overmix the dough here. The goal is for the ingredients to combine into a smooth cookie dough.

Cover cookie dough with cling film and refrigerate overnight (or at least 4 hours).

Remove the cookie dough from the refrigerator about an hour before processing and let it warm up slightly. Preheat the oven to 175°C (350°F). Scoop out about 50 grams of dough and roll it into a ball between your palms. Roll the dough balls in sugar and place them on a baking sheet lined with parchment paper, leaving enough space between them. Repeat this process until all the dough is used.

Bake cookies at 175°C (350°F) for 15 minutes. After about 15 minutes, or when the edges are slightly crisp and the center has risen a bit but still looks somewhat raw, remove the baking sheet from the oven and tap it firmly once or twice on the work surface. Then return it to the oven for another 2 minutes, until the edges are slightly crisp and the center has risen slightly again.

Remove the baking sheet from the oven and tap it firmly on the work surface once more so that the cookies are now nice and flat. Place the cookies on a cooling rack and let them cool completely.