Ever since she won the National Council Auditions in 2005 with an aria from Die Zauberflöte, Susanna Phillips has dazzled in the music of Mozart on the Met stage. Now, as she prepares to sing her fifth of the composer’s heroines with the company—the Countess in Le Nozze di Figaro, opening this month—the Alabama-born soprano spoke to the Met’s Christopher Browner about everything Mozart.

What is it like to perform Mozart’s operas, which are often musically and dramatically intimate, in a house as expansive as the Met?
Susanna Phillips: It’s a grand experience—it’s Mozart on the big stage. Part of the beauty of his music is how flexible it is. It can be done in a variety of spaces effectively, and you will hear it in a different way in a 4,000-seat house as opposed to a much smaller space, but is that bad? No, I think it’s a good thing. It gives us perspective.

The Countess is a role you’ve performed a lot throughout your career.
Yes. I first sang it at Music Academy of the West in 2003, and I’ve done at least six, maybe more, different productions since then. Really, I lose count.

Do you approach the role differently than you did when you first started singing it?
I don’t sing it as slowly. I think I was searching for a deep sense of loss and betrayal in “Dove sono” [as the Countess laments her husband’s infidelity and hopes that their marriage can be saved] by singing it slower. But actually, I think it’s more effective when it moves slightly faster. You start off feeling very sad, but then, you add all these layers that add energy to the tempo—she’s angry, she’s hurt, she’s anxious. It’s not just sad and lost.

It’s probably unfair to ask you to pick a favorite moment in a score so full of sublime music, but what are some of the scenes that stand out most to you?
The first moment that I ever fell in love with in the opera comes in the middle of Act II, when the Countess, Figaro, and Susanna are begging the Count to allow Figaro and Susanna to get married. And as they sing “Deh signor, nol contrastate” [“Oh, my lord, don’t oppose it”], the double basses play these rich low Cs—it always gives me goosebumps. It’s too short! You want it to keep going and going. Most recently, I’ve enjoyed singing the Countess and Susanna’s letter duet [as they hatch their scheme to catch the philandering Count red-handed] the most. On the surface, the music is beautiful, but it’s also so full of drama—but not in an overdone way.

I remember hearing you sing the Countess in Santa Fe in 2013, and you added some subtle ornamentation to your music, which is very unusual these days in Mozart.
In Mozart’s time, it was expected that there would be ornamentation. Sometimes, when he was writing for a singer with less experience, he would write the ornamentation into the aria, but in other places, he would have left it up to the singer. The music can still be very effective without ornamentation, but sometimes it can certainly add to the emotion. And it also makes a big difference what the direction of the scene is. Ornamentation can really help steer the character toward a particular direction.

How do you decide what ornaments to add?
The conductor certainly has an opinion about whether to include ornamentation at all, but if I am ornamenting, it must come organically. So it changes from performance to performance. If it doesn’t feel honest one night, I won’t do it. Or if a slightly different gesture feels more honest, then I’ll try something different.

I would imagine that you also find that kind of flexibility in the speech-like style of the recitatives.
The recits are where all the action happens. They have a far less musical structure, so you can mold them into anything you want. You can have some that may be playful, but at the same time, just by changing the tempo or the dynamics, they become tremendously sincere. And the beauty of experience in a role is exploring many different ways of approaching the same lines.

How spontaneous can you really be from performance to performance?
Very. When I sang Donna Elvira last season with Peter Mattei, who’s just an absolutely brilliant Don Giovanni, every performance was completely different. The way we interpreted our characters wasn’t different, but we played with each other in the recits to keep it fresh. Some phrases would be sent as a jab and some would be sent as a gesture of reconciliation. And then they would flip in the next performance. When you’re very familiar with the part, you don’t have to be as safe and as careful, and that makes for great drama.

We don’t often think of opera offering such a level of spontaneity.
But that’s the beauty of Mozart. One of the difficult things about a lot of opera is that you’re trying to get hundreds of people to make a musical gesture at the same time in the same way. It’s like moving a huge cruise ship. Whereas in a Mozart recit, it’s just you and the harpsichordist and maybe your scene partner. You can move with much more agility and almost improvise with each other.

You have a busy Met season ahead. In addition to the Countess, you return to Musetta in La Bohème, which you’ve sung many times here, and then you close out the season with your role debut as the title character of Janáček’s Kát'a Kabanová. Do you enjoy singing in Czech?
Oh, I love it. It’s so yummy, the way it feels in your mouth. It’s very purry, like a cat. It has a lot of clear, open, almost Italian-like vowels that are great to sing, and many consonants together, which you can really taste and really express with.

What will audiences new to Kát'a find when they come to a performance?
It feels a little bluesy, like Verdi or Strauss went and got the blues. And it’s passionate, but it’s not this never-ending, over-dramatic, extended affair. The whole thing is only an hour and a half, but it’s got a lot of layers. It really draws you in.