IngredientsVegetables
Zwiebelonion
Allium cepa, the base of almost every German roast gravy, stew and onion soup. It brings sweetness and body, not heat.
The three states are very different. Slowly braised in fat it turns sweet and soft. Raw in rings it stays sharp, for instance on Handkäs. Browned too far it goes bitter, and that bitterness never leaves the pot.
In Mexikoin Mexico
Cebolla blanca is the right one and every market has it. It comes closest to the everyday German cooking onion.
Cebolla morada is milder and dyes everything pink. For onion gravy, Zwiebelkuchen and braised onions take the white one; the red one belongs raw in a salad.
Kaufenbuying
Firm bulbs with dry skin, no soft neck, no green shoots.
Onions vary a lot in size. When a recipe calls for two onions it means an amount: with very large bulbs, cut it back by eye.