Allow the butter to come to room temerature and mash it with a fork.
Add miso paste, orange zest and orange juice. Mix with a fork or spatula, until well combined.
Use right away or tightly wrap in plastic wrap or parchment paper, shape into a log and store in the fridge.
Notes
Use salted or unsalted butter - per your preference (I prefer salted)
Can substitute with other citruses like lemons, limes, tangerines, or Meyer lemons.
Store wrapped as a log in plastic wrap or parchment paper. Alternatively, store it in a small glass jar or butter bell.
Can keep in the fridge for up to a week or freezer for a few months.
Remove the butter from the refrigerator about 20-30 minutes before making the recipe, so the butter can get to room temperature. To speed things up, cut up butter into smaller chunks.