Onion

Preparation

Thinly sliced; raw for a sharper bite or pre-cooked/caramelised for sweetness

Releases moisture as it bakes; thin, even slicing helps it cook through in a short bake

Applied before baking.

Cautions

• thick raw slices can remain undercooked and overly sharp in a short bake

History and cultural context

One of the oldest cultivated vegetables, used across virtually every global culinary tradition. On topped flatbreads specifically, thinly sliced onion is one of the least regionally exclusive toppings in this catalogue — it appears as a defining ingredient in otherwise unrelated traditions, from Alsace's crème-fraîche-based flammekueche to many Italian, Middle Eastern, and South Asian topped-bread traditions.

Used raw, roasted, or caramelised as a standard topping internationally.

• The Oxford Companion to Food — Oxford University Press
• Flammekueche — Wikipedia

Pairs well with

• Oregano (dried)

  Explicitly noted as a good balance for Onion.

• Fried egg (post-bake)

  Adds textural contrast against Onion. Best added fresh after baking, for brightness against Onion.

• Pepperoni

  Adds textural contrast against Onion.

• Soppressata

  Adds textural contrast against Onion.

• Guanciale

  Adds textural contrast against Onion.

• 'Nduja

  Adds textural contrast against Onion.

Styles using this topping

• SfincioneDefiningGenerally accepted

  Caramelised onion is a defining flavour component of this style, contributing sweetness against the sharp cheese and anchovies.

• FugazzaDefiningGenerally accepted

  A generous cooked-onion layer that carries the pizza's entire flavour in the absence of sauce or cheese.

• FugazzetaTraditionalGenerally accepted

  Tops the stuffed cheese layer with a sweet, savoury cooked-onion finish, the same defining topping as fugazza.

• Brazilian pizzaRegionally commonLimited evidence

  A common secondary addition alongside chicken and other Brazilian-favoured toppings.

• Ohio Valley-style pizzaDefiningSupported, with regional variation

  Provides a fresh, sharp, crunchy contrast against the warm baked cheese pizza beneath it.

• Flammekueche (tarte flambée)DefiningGenerally accepted

  Sliced thin enough to cook through during the very brief, very hot bake, forming half of Flammekueche's defining two-ingredient topping.

How it behaves on a pizza

How preparation changes what this ingredient contributes to the bake and the flavour.

• Onion: raw, softened, or caramelised

  Raw onion stays pungent and sharp on a short bake and can dominate everything around it. Softened onion is mild and sweet. Caramelised onion is a different ingredient again — deeply sweet, jammy, and closer to a condiment than a vegetable.