Cooking most varieties of fish that you find at the supermarket or fishmonger is pretty straightforward. White fish are mostly mild-flavored, varying primarily in the firmness of their flesh. Salmon is richer-tasting, but -- like white fish -- provides a nearly blank canvas for a cook's creativity. Stronger-tasting oily fish, including mackerel and fresh sardines, have a lot more personality. You'll need to adapt your meal plan taking this into consideration, but your award will be bold flavors and memorable dishes.
A Quick Fatty-Fish Primer
Sardines and mackerel are both oily fish, meaning they're rich in heart-healthy Omega-3 fatty acids. It also means they're quick to spoil, so freshness is crucial. They're best when purchased right from the boat or, if that's not an option, soon afterwards from a reputable fishmonger. Choose fish with round, clear eyes, good color -- glistening black and silver, not dull gray -- and vividly red gills. If you sniff them, you should detect only the clean, fresh, briny smell of salt water. If they smell "fishy," they probably aren't fresh.
If your sardines or mackerel feel oddly rigid, don't worry. It means they're going through rigor mortis, and it's a definite sign of freshness. They'll return to normal within a few hours, and be ready to cook.
Preparing Fresh Sardines
Your first meal of fresh sardines will be a revelation, if you've only encountered them canned. Numerous species are sold as sardines, most of them herrings or close relatives. They're small, so allow three or four per portion. Ask your fishmonger to scale and clean them for you, if possible. If that isn't an option, cleaning and deboning your own is simple enough.
- Whole sardines are excellent when simply grilled, over gas or charcoal. They need just 3 or 4 minutes per side to be fully cooked under a crisp skin.
- You can also grill sardine fillets skin-side down, ideally in a fish-grilling basket to prevent them breaking as they're handled.
- Alternatively, broil whole fish or fillets for just a few minutes in your oven, or pan sear them in a hot skillet.
Mackerel are an unusually handsome fish, with the sleek, streamlined shape of a fast-swimming predator. They don't require scaling before you cook and eat them, which makes them easier than most other fish to clean and fillet. Allow one to two fillets per person, depending on the size of the mackerel and the appetites of your diners.
Mackerel are also best when prepared through direct, high-temperature cooking methods. Broiling, pan searing, roasting and grilling are all excellent choices.
A Few Serving Suggestions
In countries where fresh mackerel and sardines form a cherished part of the cuisine, they're typically served with tangy, acidic accompaniments to act as a foil for their rich flavors. You pair cranberries with turkey, or applesauce with pork, for the same reason.
Squeeze lemon or lime wedges over the cooked fish, or try a salsa filled with the fresh flavors of tomatoes, onions and chilies. In Spain, the cooked fish might be drenched in a vinegar-based marinade to make escabeche. Pungent flavors pair well with mackerel and sardines, as well. Mediterranean recipes often add garlic, strong herbs and olives to the dish, or the fish might be served with a pungent olive-based spread called tapenade.