A blooming onion, onion bloom, onion blossom, or onion 'mum is a dish consisting of one large onion which is cut to resemble a flower, battered anddeep fried. It is served as an appetizer at some restaurants.

The dish was created by chef Jeff Glowski in New Orleans and first appeared on the menu of Russell's Marina Grill in that city as 'Onion Mumm.'[citation needed] It was popularized nationally when it appeared as 'Bloomin' Onion,' a charter feature of the Outback Steakhouse when that national chain opened in 1988. The dish remains prominent on its menu. The owners of Scotty's Steak House in Springfield, New Jersey also claim to have invented this dish in the 1970s.[citation needed] Its popularity has led to its adoption as an appetizer at various other restaurant chains, most notably Lone Star Steakhouse & Saloon,[citation needed] where it is best known as the "Texas Rose." The blooming onion is usually served with a restaurant-specific signaturedipping sauce.

Despite the implied association with Australian cuisine due to Outback Steakhouse's branding, the dish is unknown in Australia and rarely served outside of the United States.