Toni Patisserie and Cafe at 65 E. Washington St. is baking dozens of French pastries daily for the show, which opens Wednesday and runs through Nov. 10.
For 45 performances, that's 2,160 almond tarts, cream puffs, macarons and meringues.
In the play, the character Ragueneau, played by Ross Lehman, is a pastry chef and poet. Key scenes take place in Ragueneau's bakery, including one where he rhapsodizes about an almond tart.
"That was something very specific that they needed," Toni Patisserie owner Toni Marie Cox said.
In another scene, some of the actors walk around nibbling pastries out of paper cones.
The theater's props department made some fake pastries to fill out the set, but decided to reach out to Toni Patisserie for help in keeping with the French theme, said Alida Szabo, director of audience development.
Cox is used to high-volume baking. She worked at the old Mayfair Regent Hotel on Lake Shore Drive and at the Disneyland Hotel in Paris before opening Toni Patisserie in west suburban Hinsdale in 1994. She opened the Loop location in 2011.
Cox said the theater needed pastries that the actors could easily pick up and eat by hand. She took the liberty of topping the cream puffs with a rolled fondant because it's not as messy as poured icing.
Cox's treats will be delivered daily to the theater at Navy Pier. The cast and crew will likely eat any leftovers, Szabo said.
"We're going to have a very fat cast when all is said and done," she said.
Cox also will make pastries for 350 guests during an opening night party Wednesday at the theater and more than 500 cookies for an Oct. 7 event for the theater's donors. She'll be in the audience for Wednesday's performance.
Those who don't make it to "Cyrano" can still get a taste of the show. That almond tart will be for sale for $4.95 at both locations of Toni Patisserie during the show's run.