Here is a soprano with a crystal-clear tone you could pour over ice and drink. Regula Mühlemann’s Mozart selection eschews obvious arias while showing off considerable musicality and a superior technique. In the fast final section of her aria from Der Schauspieldirektor the notes are as even, accurate and well defined as they would be on a piano; the syllables of Geme la Tortorella from La Finta Giardiniera fall in fat, clear raindrops; Sevilia’s aria from La Clemenza di Tito is beautifully done. Alle have supple accompaniments from the Basel Chamber Orchestra.