Spanish onion

US /ˈspæn.ɪʃ ˈʌn.jən/
UK /ˈspæn.ɪʃ ˈʌn.jən/
"Spanish onion" picture
1.

cebolla española

a large, mild, sweet onion, typically with a yellow or brown skin, often used in salads or for cooking where a less pungent flavor is desired

:
For the salad, slice a Spanish onion very thinly.
Para la ensalada, corta una cebolla española muy finamente.
The recipe calls for a large Spanish onion to add sweetness.
La receta pide una cebolla española grande para añadir dulzura.