Caldeirada is a one-pot fish stew, simple yet rewarding. You can think of it as a natural progression from the lovely Sopa Espirito Santo, because it starts out very similar: 

Per portion:

Peel and cut a medium-sized onion into thin rings. Peel and crush two or three cloves of garlic. Sautee in olive oil, then add two diced ripe tomatoes and two or three firm and waxy potatoes, peeled and cut into large chunks. Add 300ml cold water and bring to a gentle simmer. 

Add half a teaspoon of ground coriander and ground cumin each, and a slightly smaller amount of turmeric, crushed black pepper and hot chilly powder. Also add a chicken or vegetable stock cube. Simmer gently until the potatoes are cooked (approximately 30 minutes). You may want to add some chorizo or linguica sausage (cut into thick slices) after 15 minutes for deeper flavour. 

Meanwhile, prepare the fish. Monkfish is an excellent choice if you're patient enough to clean away all the skins (not just those which the fishmonger will remove for you). Most other whitefish will also work, or you could use seafood from the freezer if you were desperate. Cut in pretty large chunks. 

Cut some stale or fresh nice bread (anything but British standard factory bread) into thick slices, rub with garlic, soak in olive oil and fry on the griddle until crisp, then cut into croutons. 

When the potatoes are done, turn down the heat and wait until the caldeirada no longer simmers, finish the seasoning, then add a handful of pitted black olives and the fish. Turn the heat off and wait 10 minutes, then serve with the croutons and a chilled white wine.