Outback Steakhouse is an American chain, using an "Aussie" theme for marketing only. There is nothing authentic about it (unless they serve Fosters).

The "Bloomin' Onion" is the Outback Steakhouse version from a dish of American origin(a NJ steakhouse claims "firsties", but you know how that goes). It's called by different names by whoever is selling it. The basic principle is the same: a large sweet onion, cut with a special bladed tool, battered and deep fried. The variations come from the batter and dipping sauce recipies.