Have been wondering about compound butters.

I've got a jar of unopened saffron I bought last year and was debating on
making a compound butter with that. Waste of saffron?!?

Another is rosemary. I think that's a common version?

What are some of your favorite compound butters and maybe a recipe?

I'm stuck with diet margarine lately so it can use all the help it can get!

Thanks in advance,

Andy