Can I cook fish straight from frozen?

Cooking fish from frozen is not a compromise for people who forgot to plan. For thin, delicate fillets it is often better, because the thawing process is what does most of the damage — ice crystals rupture cells, the fillet slumps and it releases water. Going straight from freezer to heat skips that entirely.

Step by step

1. Rinse the ice glaze off under a cold tap and pat dry.Ten seconds under cold water removes the surface frost, which would otherwise turn to steam and stop any browning. Dry the fillet immediately and thoroughly.
2. Choose a method that surrounds the fish rather than blasting one face.Oven, grill, steamer, poaching liquid and a parcel all work well because the heat has time to reach the centre. A screaming hot pan burns the outside before the middle thaws.
3. Drop the temperature and extend the time.For the oven, about 180°C rather than 200°C, and roughly half again to double the time you would give a thawed fillet — a standard portion typically 20 to 25 minutes. Judge by the fish, not the clock.
4. Season after the first few minutes, not before.Nothing sticks to a frozen surface. Give it five minutes, take it out, brush with oil and season, then return it. That also lets you check progress.
5. Test at the thickest point.A knife tip or skewer should slide into the centre with no resistance and the flesh should be opaque and flake apart. A cold or resistant centre means back in the oven, not longer at higher heat.
6. Use foil or a parcel for thin fillets.Plaice, sole and small fillets keep their shape from frozen when they are cooked in a sealed parcel with a little butter and lemon, which also handles the extra moisture released.
7. Pan-fry only thick pieces, and start covered.A thick frozen loin can be pan-cooked if you start it in a moderate covered pan to thaw the centre, then uncover, raise the heat and finish for colour. It will never crisp as well as a thawed fillet.

Tips

• Frozen prawns go into a curry, soup or stir-fry directly and need no thawing at all — they cook in about the time everything else needs anyway.
• Breaded and battered fish sold frozen is designed to be cooked from frozen and should never be thawed first; the coating goes soggy and slides off.
• Mussels and clams sold frozen are already cooked. They need heating through only, and the alive-or-dead sorting rules do not apply to them.
• Expect a little more liquid in the tray than with a thawed fillet. Pour it off before saucing rather than serving fish in it.

Common mistakes

• Deep-frying fish from frozen — Ice hitting hot oil boils violently and can throw oil out of the pan. It is genuinely dangerous with a domestic pan, and the coating detaches anyway.
• Raising the oven temperature to make up the time — The outside dries and toughens long before the frozen centre catches up. Lower and longer is the whole approach — heat has to travel further, not harder.

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