Adding the ingredients in the right order is the secret to this recipe's success; the ones that take longest to cook go in first. The optional layer of seaweed (available from most fishmongers) imparts a salty ocean essence and keeps the potatoes off the bottom of the pot.
You'll have this dish on the table in under 15 minutes. (No, we're not kidding.) Serving it with lots of crusty bread is a must: You'll want to sop up every last drop of broth. We love the hint of anise from the tarragon.