Boiled Cod

Ingredients

• cod fish
• water
• 120 ml vinegar
• hard-boiled eggs

Method

The overnight vinegar soak is the crux here. Acetic acid denatures the cod's proteins and firms the flesh, preventing the mushy disintegration that comes from thermal shock alone. This is especially critical for thick centre-cut fillets or whole fish. Soak in cold water with 120 ml vinegar for at least twelve hours — the brine equilibrates the flesh and seasons it evenly.

Drain the fish and rinse thoroughly under cold water until the smell turns clean and faintly briny, not vinegary. Pat dry. Place in a fish kettle (or deep, narrow pan) with fresh cold water; the liquid should just cover the fish. This matters: a tight fit prevents it rolling and breaking apart. Bring to the gentlest simmer — you want a whisper of steam and the occasional bubble rising from the bottom, not a rolling boil. Vigorous boiling causes the muscle fibres to contract violently, squeezing out moisture and toughening the flesh. The slow ascent to temperature (twelve to fifteen minutes for a 300 g fillet, longer for whole fish) allows the heat to penetrate evenly.

Once simmering, skim the surface once or twice in the first few minutes. A grey-brown scum will rise — this is denatured protein and impurities. Get it off; it muddles the flavour. After that, leave it alone. The fish is cooked when the thickest part flakes apart at the gentlest pressure from a fork and the flesh has turned opaque white, not translucent. There's no recovery from overcooking cod; stop the moment it flakes.

Carefully transfer the fish to a warmed platter lined with a clean cloth or napkin — this absorbs excess liquid and steadies it. The cloth also keeps it warm. Halve your hard-boiled eggs lengthways and arrange them around the fish in a ring. The yolk's richness and the white's mild sweetness cut through the cod's lean, faintly sweet flesh. Serve immediately with the cooking liquid spooned over, plus parsnips on the side.