Tropea, Vibo Valentia province, Calabria — the cipolla rossa di Tropea has been cultivated on the narrow Tyrrhenian coastal strip between Nicotera and Pizzo since ancient times; Greek and Roman sources reference the Calabrian coast's sweet onions. IGP status granted in 2008.
Cipolla rossa di Tropea IGP is the sweet, brilliantly crimson onion of the Calabrian Tyrrhenian coast — grown in the marine-influenced sandy soils between Nicotera and Capo Vaticano, harvested from June through September. Unlike standard red onions, the Tropea onion is remarkably sweet (low sulphur content from the coastal soil) and can be eaten raw without the harsh bitterness of inland onions. The primary preparations: consumed raw in salads with just olive oil and salt; made into cipolle sott'olio (pickled in olive oil with peperoncino); made into a slow-cooked condiment (marmellata di cipolla di Tropea — onion jam) for cheese and cured meats; or used raw atop bruschetta. The raw eating of sweet onion is the most radical demonstration of the onion's quality.
Cipolla rossa di Tropea raw, sliced thin and dressed with olive oil and salt, is one of the simplest pleasures in Italian cooking — the onion is brilliant crimson, almost translucent, and astonishingly sweet. There is almost no sulphur bite; eating a slice raw produces only sweetness and a light, clean onion flavour. It is the demonstration that terroir applies to vegetables as much as wine.
For the raw salad: slice Tropea onions thin; dress with excellent olive oil, salt, and possibly a drop of lemon juice — nothing else. The onion should be sweet enough to eat in volume without eye-watering. For the onion jam (marmellata): slice onions thin; cook covered in olive oil over very low heat 30 minutes until completely collapsed; add red wine vinegar and sugar; continue uncovered until jammy and dark. For sott'olio: blanch in vinegar-water 3 minutes; drain; pack in sterilised jars with olive oil, peperoncino, and bay.
Tropea IGP onions are available in UK and European markets in summer from specialist Italian greengrocers and some farmers' markets. The distinction between Tropea and ordinary red onion in raw preparations is dramatic — if you have never had it, the Tropea onion eaten raw is one of the revelatory Italian vegetable experiences. The onion jam makes an extraordinary accompaniment to Pecorino Crotonese or Caciocavallo Silano.
Substituting regular red onion for Tropea onion in raw preparations — the result will be unpleasantly harsh; if Tropea is not available, cook the onion rather than using raw. Over-cooking the jam — onion jam should be a deep, glossy condiment, not caramelised to bitterness. Under-seasoning the raw salad — Tropea onion raw with olive oil and salt is a complete preparation; over-complicating it obscures what you are showcasing.
Slow Food Editore, Calabria in Cucina; Giorgio Locatelli, Made in Italy