Any kind of compound butter works well. The crabs down here are just starting to moult, last year we had a really long softy season, well into July. If your blues are big enough to pick for lump meat you can make a crab cream with the bodies and fold in the lump and cheese at the end and make a great gratin. Or make a soup with brandy and cream. You get a lot of crabby bang for your buck making soups and sauces with the bodies of picked blues.