Who is this actress?

Her middle name is Louise. She's won Oscars for Best Actress in a Lead and Best Actress in a Supporting Role. Dustin Hoffman, Robert DeNiro, Christopher Walken, Robert Redford, Jack Nicholson, Bruce Willis, Gene Hackman, Nicholas Cage, Denzel Washington, Jim Carrey and Clint Eastwood... just to name a few. Who am I?