There is a new gadet on the market that is actually a reproduction of the device used to keep butter without refrigeration for many many years.
It's ceramic and shaped like bell with a handle on it, and comes with a small bowl to set it in.
You turn the bell upside down and spoon all the butter into the inside of the bell. Then you put a little water in the bowl to make an air seal, and set the bell down in the bowl. Butter keeps a long time doing this, right on your table, and it's always soft and spreadable.
Here is one company that makes them.