The Coen brothers have won one Oscar for best feature film. For which film did they win?

Explanation

The two Coen brothers, Ethan and Joel, have become cult directors with big hits such as 'The Big Lebowski', 'Fargo', 'O Brother, Where Art Thou?' and not least 'No Country for Old Men', for which they won an Oscar for best feature film. Their big strength are their very colourful characters such as the cynical barber in 'The Man Who Wasn't There' and not leas the White Russian-drinking 'The Dude' in 'The Big Lebowski'. The Coen-brothers tend to cast the same actors: George Clooney has been cast thrice, John Turturro four times.