Stage Review

THE CAKE

Play by Bekah Brunstetter.

Directed by Jennifer Chambers. Presented by Barrington Stage Company. At St. Germain Stage, Pittsfield, through July 15.

Tickets $15-$55, 413-236-8888, www.barringtonstageco.org

PITTSFIELD — Even on a mediocre sitcom like “That ’70s Show,’’ it was impossible to miss Debra Jo Rupp’s talent as an actress.

So it’s not really a big surprise that Rupp delivers such a gem of a performance when she gets a crack at the lead role of a topical play with the heart, smarts, wit, and humanity of Bekah Brunstetter’s “The Cake,’’ now at Barrington Stage Company. Rupp brings shadings of nuance to a character who at first seems to be an open book.

She plays Della, the fervently devout owner of a North Carolina bakery, who is so gifted at making cakes that she’s been chosen as a contestant on television’s “Great American Baking Show.’’ Whether it involves a recipe for pineapple upside-down cake or scriptural injunctions from the Bible, Della is a firm believer that one must, as she puts it, “Follow. The. Directions.’’

Then her world is jolted when Jen (Virginia Vale), the adult daughter of Della’s deceased best friend — whom Della loves as if she were her own daughter — reveals that she is a lesbian. And that she’s about to marry the cosmopolitan girlfriend, Macy (Nemuna Ceesay), with whom she has been living in New York. And that Jen would like Della to bake the wedding cake. A reeling Della suddenly finds herself locked in an epic wrestling match between her religious convictions on the one hand, and, on the other, her uneasy conscience. Then there’s the matter of troubles in her own marriage that have left her deeply hurt.

It adds up to a lot of thematic weight for what is fundamentally a comedy, and “The Cake’’ totters at times under that weight. There are moments when it seems that playwright Brunstetter is in danger of didactic lesson-mongering, or building a facile bridge across the Red State/Blue State divide, or engulfing us in toothache-inducing sentimentality.

But none of these envelop, or come close to defining, this top-notch production. Credit for maintaining the right balance belongs to Brunstetter, a supervising producer on NBC’s “This Is Us,’’ but also to director Jennifer Chambers and to her exemplary cast, which includes Douglas Rees as Tim, Della’s good-hearted but oblivious husband. They ensure that we understand the stakes for all involved in this dilemma.

In a clever device, the unseen voice of Della’s conscience — or is it the voice of a higher authority? — is heard in fantasy sequences when Della is quizzed by George, the baking show’s host, who — in an apparent nod to “The Great British Baking Show’’ — speaks in an English accent, and who grows increasingly judgmental about Della’s decision. (George is played by Morrison Keddie, who is married to playwright Brunstetter.)

In less skilled hands, Della could easily be a caricature, and in truth she does register as a cartoonish figure at first, denouncing tofu and extolling the virtues of butter and milk as she blithely confides in Macy her faith in the transformative power of cake. “I read about what’s going on with ISIS and I think to myself, if cake were just free for everybody, there would really be a whole lot less problems in the world!’’ she says. But there are more layers to Della than meet the eye, and Rupp makes that complexity believable. (Rupp pulled off a somewhat similar feat six years ago at Barrington Stage when she brought dimension to her portrayal of sex therapist Dr. Ruth Westheimer in Mark St. Germain’s “Dr. Ruth, All the Way,’’ later retitled “Becoming Dr. Ruth’’ when it moved off-Broadway.)

As Jen, Vale movingly communicates the residual loyalty she feels to her conservative roots, and how much of the small-town girl remains in her, especially when Jen hears the region where she grew up casually disparaged at New York parties. Ceesay is equally compelling in her portrait of Macy as a fighter who believes in unambiguously declaring the difference between right and wrong, and is furious that her girlfriend is still battling vestiges of the shame instilled in her by her upbringing. Macy is a force for moral clarity.

And Della? What values will she ultimately embrace? Might she come to realize that the pursuit of happiness can take many forms?

Rupp does a beautiful job of keeping us guessing while signaling how wracked Della is by internal conflict — and keeping us laughing, too, sometimes with the smallest gesture. When Macy asks if she has any soy coffee, Rupp’s Della cocks her hip like a matador determined to turn aside a charging bull, then flatly answers no.

THE CAKE

Play by Bekah Brunstetter. Directed by Jennifer Chambers. Presented by Barrington Stage Company. At St. Germain Stage, Pittsfield, through July 15. Tickets: $15-$55, 413-236-8888, www.barringtonstageco.org

Don Aucoin can be reached at aucoin@globe.com. Follow him on Twitter@GlobeAucoin