Ten years after Twin Falls Idaho premiered at Sundance and established Michael and Mark Polish as darlings of independent cinema, the brothers return to Park City this month with Manure, one of two films they shot back-to-back last summer.

A satirical riff on the US salesman archetype, Manure, which screens in the festival's non-competitive Premieres section, takes place in 1960s Nebraska and stars Billy Bob Thornton (lead in the brothers' 2006 studio release The Astronaut Farmer), Tea Leoni and Kyle MacLachlan.

Shooting began in Southern California late last May and when production wrapped the brothers did not wait around; in late July they began filming another comedy, a John Sayles homage called Stay Cool that stars Winona Ryder and Chevy Chase.

"At the start of last year, the SAG strike was looming and we were in the middle of the writers' strike," Mark says from an editing suite in Santa Monica. "Our studio work, and especially the writing, was frozen.

"We had some screenplays and thought it could be a while before things got resolved so we wanted to do two films quickly. We used the same crew and shot Manure entirely indoors and Stay Cool on location in the nearby area."

The comedies are the first films to emerge from Prohibition Pictures, a partnership the brothers launched in early 2008 with financier-producer Ken Johnson and his business partner Janet DuBois, both of whom produced Manure with the brothers and their longtime collaborator Jonathan Sheldon.

"The Astronaut Farmer was perceived to be a studio film, so people were asking if we were out of the indie game," says Mark. "But we felt indie film-making was alive and well and there were still films to be made in a certain budget range. Indies aren't dead."

Manure and Stay Cool (which is not screening at Sundance) cost just under $10m and around $5m, respectively. Of Manure, Michael says: "Billy's character has to go into the farming community and sell manure. The movie's about how these people exist and the competitive nature of their business."

The brothers divide up the tasks of film-making: Michael directs and they both write and produce. Mark also has featured roles in both Manure and Stay Cool (worldwide rights are still available for both films).

"If we were just producers, I don't think these movies could have been done the way they were," Michael says. "Because we were also writers and directors, we were able to see the process through in the way we envisioned it."