If you should ever have the distinct pleasure of getting a whole lobster all to yourself — perhaps with a little cup of drawn butter and a plastic bib — it can be tricky to know exactly where to start. Most people will tell you that the first thing you should do is grab hold of the thing and twist it in half, separating the body from the tail (it’s not for the squeamish, but it really is the best way to get going). Take a peek inside the body and you’ll notice that there’s probably quite a bit of green stuff in there. What is that, exactly?
That green gloopy stuff is called the tomalley (or sometimes the mustard), and it’s actually a pretty useful ingredient in lobster-based foods because it has a seriously concentrated lobster flavor. It’s mixed into sauces, stuffings, and compound butters to boost the flavor, and some people just like to eat it straight (the equivalent of “sucking the head” of a crawfish or shrimp). It’s also a major flavor component of lobster bisque and stock.
Even though some people think of the tomalley as the “guts” or roe of the lobster, in reality it’s actually a specialized organ called the hepatopancreas, the same thing that’s sucked out of crawfish and shrimp for its flavor. The hepatopancreas provides the functions of both the liver and pancreas; namely absorption of digested food and production of digestive enzymes. In reality, it’s probably best if you don’t think about it; just know that it tastes good.