Itlog na Maalat (Filipino Salted Duck Eggs)

Method

1. Under a bright light, discard eggs with a hairline crack, leak, odor, or stubborn dirt. Use only clean eggs and wipe loose dust from sound shells with a dry paper towel.
2. Wash a nonreactive 2.5–3 litre wide-mouth jar or two smaller jars, lids, and a glass weight in hot soapy water; rinse and air-dry. Add the eggs without packing tightly.
3. Boil the water and salt, stirring for 3 minutes to dissolve. Cover and cool the brine completely to room temperature.
4. Pour cool brine over the eggs and add the clean weight so every shell stays submerged. Cover, date, and keep in a dark, dry spot at 18–22°C.
5. Inspect the covered jar daily without touching the brine. Discard any cracked egg; discard the batch for slime, mould, or foul odour. At day 18, remove one egg cleanly, cover with cold water, bring to a gentle boil, then cook for 20–25 minutes until hard-boiled. Cool and cut open to check that white and yolk are fully set; never test it raw.
6. If the cooked yolk is firm, rich, and salty enough, proceed. Otherwise cure for another 3–7 days and test another cooked egg. Stop by day 35; if the area cannot stay at or below 22°C, use commercially cured eggs instead.
7. Drain the eggs and discard the brine. Cover with fresh cold water, bring to a gentle boil, then cook for 20–25 minutes until whites and yolks are fully set; allow longer for particularly large eggs. Use the same fully cooked endpoint as for the test egg.
8. For red shells, combine hot water, vinegar, and colouring; dip the cooked eggs for 1 minute. Colour identifies but does not preserve them, so leave them plain if preferred.
9. Cool promptly in cold water, dry the shells, and refrigerate covered. Use within 1 week and never leave cooked eggs out for more than 2 hours.