In Denmark they've sold Lurpak Parsley butter for years as the Danes always have it with baked potatoes.. very nice.
Do you have a parsley grinder? If not then chop fine and mix with butter that room temperature, don't heat it up.
When mixed you can even do your own little shapes before putting it back in the fridge. I tend to mix a load and then I roll it into a log, wrap in foil and stick in the freezer. That way it keeps forever and I take it out and cut how ever many slices I need and put it back in the freezer