Christine Schafer is not only one of the most talented singers in the world today, but also one of the most versatile. When she came through town in 2002, she scored an impressive hat trick, starring in Berg’s “Lulu” at the Met, giving a fine recital at Alice Tully Hall that included not only pieces by Schubert and Schumann but also George Crumb, and, most surprisingly for me, blowing the doors off Avery Fisher Hall with an Olympian performance of concert arias by Mozart.

Fresh from Friday night’s golden recital (see Jay Nordlinger’s review on this page), Ms. Schafer returned to the stage on Sunday afternoon for a somewhat more well-tempered performance of Bach and Handel. Her partner this day was the fine Freiburg Baroque Orchestra, a smallish ensemble – 16 musicians in its largest iteration – that, despite its name, performs all types of concert music from the early to the contemporary.

Opulent weddings, even royal ones, fade in the memory; but imagine the special present that one anonymous Leipziger was able to give to his bride: A new cantata by Johann Sebastian Bach. Ms. Schafer used an entirely different voice for this type of singing than anything we heard on Friday evening: campanilian, the mood philosophical in spots, devout in others, the style somewhat flat but allowing for vibrato where appropriate. She recognized the need for some emotion and even a little melisma, unlike a respected singer like Emma Kirkby, who completely shuns vocal ornamentation but is mistress of controlled intensity. Most of Ms. Schafer’s solos were echoed by a Freiburg oboist performing on a period instrument that looked like an alto recorder with a double reed.

The New York City Opera will present Handel’s “Orlando” in March and this concert was a good preview, since Ms. Schafer used her operatic voice – yet another incarnation of this protean artist – to perform two arias from “Alcina,” which is part of the same Orlando Furioso trilogy. The two pieces are the alpha and omega of the emotion of the sorceress, the first expressing her love for an unattainable man and the second her vengeance upon him. Hearing Ms. Schafer let loose with a full-blown opera house rendition, especially in the latter (“Ombre pallide”), made me rethink a few good reviews that I recently gave other sopranos. Ms. Schafer is expert at character development and sends chills when she revs up this exceptional instrument. One of her most noticeable qualities is her ability to make the most difficult type of singing look ridiculously easy. And she can give Cecilia Bartoli a run for her money for sheer vocal filigree.

What absolutely amazes me, however, is her ability to sound entirely different when the repertoire demands it. Her lieder, her opera, her church music, her contemporary music, have in common a noticeable intelligence and relevance, but literally sound like they are being sung by different artists. It is extremely rare to find a singer who is so highly proficient and equally at home in the classics and the music of our own time – in fact, the only other at this level who comes to mind is Ewa Podles. Christine Schafer should be savored and treasured as often as possible, especially since her appearances in the U.S. are extremely rare.

The orchestra acquitted itself splendidly throughout. Conductorless but led by concertmistress Petra Muellejans, they took a downsized approach to Bach and Handel but not a fundamentalist one. This is an interesting hybrid of some period instruments and some modern, with a healthy respect for vibrato. The Suite No. 1 for Orchestra of Bach was notable for its variations in tempi, each of the French dances played at a different speed. The sound might be described pejoratively as spare or enthusiastically as clean. It really depends on which side of the fence the listener sits in these contentious times of Baroque scholarship.

The high strings were particularly eloquent in Handel’s “Entrance of the Queen of Sheba” from “Solomon,” deploying rapid dynamic changes. Finally, these highly dedicated musicians gelled wonderfully in the Concerto Grosso Op. 3, No. 2. Not everyone’s cup of tea, perhaps, but some didn’t care for those transcriptions of Bach for 100 musicians by Leopold Stokowski, either.

***

The careers of American composers Aaron Copland, Virgil Thomson, Walter Piston, Elliott Carter, Roy Harris, David Diamond, Elie Siegmeister, Irving Fine, Easley Blackwood, Arthur Berger, John Vincent, Harold Shapero, Marc Blitzstein, and Philip Glass were all significantly influenced by a woman whom none of them had ever met. Her name was Lili Boulanger.

Lili’s graduation piece, the cantata “Faust et Helene,” won the Grand Prix de Rome in 1913. She was the first woman to be so honored. She composed two symphonic poems, several choral works with orchestra and a song cycle, and was working on an opera, “La Princesse Maleine,” when she died in 1918 at the ridiculously young age of 24. Her sister was deeply affected by her death and soon realized that she could never match her sibling’s sensitivity as a composer. So she abandoned her own aspirations in the field and retreated to the profession of her father and grandfather; it was here that Nadia Boulanger achieved her great stature as the most influential pedagogue of 20th-century music.

Having the opportunity to hear any of the songs that she so cherished and admired is a rare treat, but when I saw they would be coupled with those of Alma Mahler – another woman who had a major influence in roughly the same contemporaneous arena – Thursday’s recital by mezzo Susanne Mentzer at Zankel Hall seemed a must hear.

I first encountered Ms. Mentzer in Houston in the 1990s,experiencing her lovely “Les Nuits d’Ete” with the symphony there. Since then, however, several of her New York events have left me wanting – not from a technical perspective, wherein she is highly proficient, but rather on the level of intensity of emotional investment.

She poured her heart into these Boulanger gems, however. Was it “Im Treibhaus” or “Tristan” that directly influenced the first piece, “Si tout ceci n’est qu’un pauvre reve”? The song is heavily perfumed with the scent of flowers just a little past their prime, and Ms. Mentzer caught the mood perfectly. “Nous nous aimerons tant” is written in a harmonic language just a little more advanced, reminiscent of the contemporary work of another unjustly neglected composer who died young, the symphonist Alberic Magnard. Ms. Mentzer handled the idiom with ease, showcasing her very impressive lower register. And her magical traversal of the two Maeterlinck songs – “Reflets” and “Attente” – sealed the impression that this set was one of the most important of the entire New York season.

At first glance, it seemed strange that all of the Alma Mahler songs were written in the same year of 1910, but in actuality they were each from an earlier time. These efforts had previously been dismissed by Gustav as interesting amateurism. After Alma had an affair with future husband Walter Gropius, however, Mahler changed his mind rather suddenly, encouraging Alma to publish her fine and worthy pieces.

His original assessment was probably closer to the truth, but these character studies are imbued with a solid sense of light and shadow and dwell in a more radical neighborhood harmonically than any of the husband’s symphonic works. The influence of Alexander Zemlinsky is palpable, and their spirit of adventurousness more than makes up for the lack of melodic invention.

Ms. Mentzer was especially adept at bringing out the subtle shadings of these “little night music” miniatures. Using some of her operatic training, she developed characterizations quickly and performed the five songs as a sort of suite that offered glimpses and flickers of a bygone era strangely nostalgic for those of us who never lived during the period. Perhaps the most charming aspect of this recital as a whole was Ms. Mentzer’s genuine and infectious advocacy for this music.

Her presentation of Schumann’s (no, not Clara’s) “Frauenliebe und Leben” was once again secure and expressive, dwelling in the more intimate regions of the restrained rather than the sometimes overblown renditions of her colleagues who incorrectly equate overflowing emotion with ear-piercing volume (this is especially true of recitals featuring the work of that other lunatic composer, Hugo Wolf). Her otherwise reliable recital partner, pianist Craig Rutenberg, did not serve her well here, however, committing several errors of commission that might have thrown a less composed vocal artist. Songs of Libby Larsen and Carrie Jacobs-Bond, who performed at the White House for both Teddy Roosevelt and Warren Harding, rounded out the program.

Zankel Hall is a rather inhospitable place for a solo singer, especially when moments of expressive quietude are desirable. Ms. Mentzer exhibited exceptional fortitude and perseverance as she battled the intrusive noise of the subway. At the Carnegie luncheon for members of the press this past week, acting director Klaus Jacobs told us all that the management had absolutely no plans to attempt to further minimize this incredibly annoying distraction. We can admire their candor, if not their commitment to excellence.