Dakin Matthews, Jessie Mueller and cast.

The trend on Broadway to turn motion pictures into musicals is often lamented, but there have been many successful adaptations. Tony Award-winner Diane Paulus, Artistic Director of the American Repertory Theater, is testing the recipe in Cambridge with the world premiere of Waitress, a tasty dish concocted by a team of top chefs. Based upon the motion picture written by the late Adrienne Shelly, the new musical features a book by Jessie Nelson, music and lyrics by Grammy-nominated singer-songwriter Sara Bareilles and a star turn by Tony Award-winner Jessie Mueller (Beautiful) as Jenna, the waitress and expert pie maker searching for the right ingredients to change her life and find happiness.

The 2007 film which starred Keri Russell has a strong story with strong characters, a very good place to start for a transfer from screen to stage. Nelson's book invents back stories for Jenna and her abusive husband Earl (a menacing Joe Tippett), tweaks the story lines for Jenna's diner co-workers Becky (Keala Settle) and Dawn (Jeanna De Waal), and fleshes out the character of Dawn's love interest, Ogie (Jeremy Morse). Cal (Eric Anderson), the seemingly humorless boss and guardian of the diner grill, and Joe (Dakin Matthews), the soft-hearted curmudgeon who owns the place, are played to perfection in supporting, yet substantial roles, and Drew Gehling (Dr. Pomatter) makes beautiful music with Mueller as Jenna's hands-on obstetrician.

Equally crucial for making the story into a musical is using the music to convey emotions that can be shown in close-ups on the screen, but need to be more grandly illustrated on the stage. In her first attempt at writing for the theater, Bareilles hits a home run, exquisitely projecting the thoughts and feelings of the characters through her eclectic score, a mixture of lush, romantic ballads and upbeat, tuneful songs with an array of rhythms. Enhanced by the creative team's intelligent song placement, she discloses information about the characters, advances the story and builds the emotional level to its peak with a trio of musical numbers in the second act. (An unfortunate caveat is that it is nearly impossible to discern the lyrics due to the overpowering volume of the onstage band.)

Paulus imbues Waitress with her vision and golden touch, balancing several key components of the story to achieve a blend of lightness and darkness that naturally reflects the human condition. None of the characters is strictly good or bad, although they have their leanings; she makes sure we see how their wounds account for their flaws, but also how they strive to be better or "happy enough." We see just enough of Jenna's loveless marriage to understand her unhappiness and the paralysis that is part and parcel of the symptomatology of a victim of abuse. It isn't necessary to see actual physical violence (and we don't), but the threat of it - and Earl's hair-trigger temper - permeates her daily existence like a toxic fume. Pomatter's discontent, Dawn's search for love, and Becky's desire for some mystery in her life all pale in comparison to the cards in Jenna's hand.

Mueller is an artistic force who is worth the price of admission. She inhabits Jenna in all aspects of her personality, from her profound sadness and her sense of futility, to the supportive friend and the hopeful lover, and finally the loving mother. Her singing is other-worldly, reaching its pinnacle in her eleven o'clock number "She Used to Be Mine," and when she joins voices with Settle and De Waal, their harmony is heavenly. Individually, these two make Becky and Dawn three-dimensional personalities and kill it in their character songs ("When He Sees Me" and "I Didn't Plan It," respectively). The three women share an authentic bond that reflects the camaraderie of co-workers who are also friends and establish the diner atmosphere that mixes homey warmth with no-nonsense hustle and bustle.

There are not a lot of dance routines per se, but Chase Brock's choreography is more about intricate movement, especially in the ensemble numbers ("Opening Up," "Waiting Room," "I Love You Like a Table"). Bareilles' score is beautifully (albeit loudly) rendered by Music Supervisor/Conductor/Pianist Nadia DiGiallonardo and five astounding musicians seated upstage on Scott Pask's movable set, looking as if they are patrons in a section of Joe's Pie Diner. When the action shifts to another location, the grill window closes and the set piece rotates, the counter and stools are rolled off, and others are rolled out - a bench and bus stop sign, the tired furnishings of Jenna and Earl's home, or an exam table in Dr. Pomatter's office. Lighting designer Kenneth Posner changes the mood and time of day by altering the hues of the sky on the backdrop, and employs spotlights to focus on Jenna when she is lost in thought while engaged in a scene with someone else. Sound designer Jonathan Deans outfits the actors with head mics, so dialogue comes through loud and clear, but here's hoping he improves the mix in the musical numbers. Completing the design team (all four of whom worked with Paulus on Finding Neverland at the A.R.T.) is Suttirat Larlarb whose costumes suit the waitresses and their patrons as if they bought them off the rack at Walmart.

Waitress is a feminist tale lovingly crafted by a female creative team, yet its themes of friendship, resilience, and following your dreams are universal. While it closely adheres to the screenplay, the story and relationships are enhanced and enriched by setting them to music. Although the women are the core, the men are well-drawn and fully representational, and all are realized by strong performances. Ultimately, they're all seeking the same thing, their slice of happiness. It's as simple as pie.

Waitress, performances through September 27, American Repertory Theater at Loeb Drama Center, 64 Brattle Street, Cambridge, MA; Box Office 617-547-8300 or www.americanrepertorytheater.org.

Book by Jessie Nelson, Music & Lyrics by Sara Bareilles, Based upon the motion picture written by Adrienne Shelly; Scenic Designer, Scott Pask; Costume Designer, Surirat Larlarb; Lighting Designer, Kenneth Posner; Sound Designer, Jonathan Deans; Wig & Makeup Designers, Rachel Padula Shufelt & Jason Allen; Script Consultant, Peter Duchan; Associate Director, Nancy Harrington; Production Stage Manager, Thomas J. Gates; Music Supervisor, Nadia DiGiallonardo; Choreography by Chase Brock; Director, Diane Paulus

Cast (in order of appearance): Jessie Mueller, Eric Anderson, Keala Settle, Jeanna De Waal, Dakin Matthews, Joe Tippett, Drew Gehling, Jeremy Morse, Giana Ribeiro, Addison Oken; Ensemble: Charity Angel Dawson, David Jennings, Corey Mach, Ragan Pharris, Cullen R. Titmas, Stephanie Torns; Swings: Emily Afton, Ben Sidell

Photo: Evgenia Eliseeva