She eventually transferred to La Scala where she debuted singing Eva in Die Meistersinger von Nürnberg under Arturo Toscanini in 1929.
She sang in the first performances of Alfano's L'ultimo Lord, Mascagni's Pinotta, Zandonai's Farsa amorosa, and Wolf-Ferrari's Il campiello, including his operatic adaptation of de Vega's play La dama Boba.
Giulietta Simionato remarked on her "animal sensuality" and said "[Favero] gave away a great deal of herself – more than was good for her – but the result was extremely moving."
Preiser have published a collection of Favero's recordings on CD in their Lebendige Vergangenheit series (Mono 89162).
The series contains the 1937 'Cherry Duet' (Suzel, buon di) with Tito Schipa from Mascagni's L'amico Fritz.