Take the butter out of the fridge ahead of preparation. If you have the time to let it get to room temperature that would be best.
Miso butter
Use a spoon to stir the miso paste through the butter. You can either go for marbled or for truly mixing it through well. I like the latter best, but one should absolutely feel free to disguise a rush by calling it a fancy style choice.
Use
You're now ready to use it any way you like, for example on a sandwich, or to wow your guests (with minimum effort) on toasts or fresh bread during apéro! This goes well with any aperitif.