The word casseroles is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 14
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (35 words)
acerose, areoles, carless, cereals, classes, closers, coalers, creases, creoles, cresols, cresses, crosses, earless, escolar, lassoer, lassoes, leasers, lessors, oarless, oracles, reclass, reclose, recoals, relaces, resales, rescale, reseals, resoles, sacless, scalers, sclerae, scleras, sealers, solacer, solaces