The makers of Little Miss Sunshine on their new film Ruby Sparks

Call it the burden of success. You score a breakout hit with your first low-budget film and then … nothing. Years pass, the world moves on and all of a suddenly that pressure to deliver again starts to become debilitating. It’s something writers and musicians know all about: the tricky second novel, the difficult second album. For husband-and-wife directorial team Jonathan Dayton and Valerie Faris, however, the reality has been somewhat different.

In the six years since their debut indie film Little Miss Sunshine secured a record-breaking $10.5m distribution deal at Sundance and went on to pick up two Oscars and gross more than $100m at the global box-office, the former music video directors haven’t been sitting at home, sweating about how to follow it up.

“We actually worked on movies continuously after Little Miss Sunshine,” says Dayton. “I think for us, it was such a profound experience, we wanted to protect the filmmaking process, and as we worked on various films it became clear they weren’t ready to be shot, even though people said, ‘Let’s go make them.’”

Also, says Faris, “every time you go to do a project you feel that fear that this could be the end of your career, so I don’t think it created any more pressure. If anything it was nice to have that experience behind us.”

Still, there is a certain irony that their new film, Ruby Sparks, ended up being the first script they deemed ready to go into production – it’s about a blocked writer struggling to follow up the enormous success of his debut novel. “Yes, we could relate to that,” smiles Faris. “Or at least, we thought it was funny that he’s facing the same thing.”

Reuniting them with their Little Miss Sunshine star Paul Dano, the film revolves around a 29-year-old novelist called Calvin, whose first book, published a decade earlier, made him a literary sensation, but in the years since has also made him too fearful to write anything more substantial than a few short stories. That all changes, however, when he “meets” the film’s eponymous heroine: a wide-eyed girl he literally writes into existence.

It was Dano who sent Faris and Dayton the script. Or, at least, it was Dano who suggested to the film’s writer, co-star, and his real-life partner, Zoe Kazan, that she send it to them, figuring correctly that they’d respond to the writing, which puts a much darker, more thoughtful spin on the premise by having Ruby (Kazan) increasingly deviate in reality from the idealised girl Calvin is attempting to write on the page.

“If Valerie and Jonathan had not agreed to work on this, we would have had a much harder time getting it made,” says Kazan. “The story is hard to talk about because it’s unusual, but that was the intention. The movies we like are hard to put in one slot and I like that this movie is hard to define.”

One of the reasons is that the film slyly interrogates gender stereotypes, particularly the idea of the “Manic Pixie Dream Girl”, an especially winsome female character type that has been springing up in American cinema more and more prominently over the past decade or so.

First defined by the American film critic Nathan Rabin in response to Kirsten Dunst’s performance in Elizabethtown, it’s a phrase that perfectly encapsulates the type of kooky girl who, as Rabin put it in his critique of that film, “only exists in the fevered imaginations of sensitive writer-directors to teach broodingly soulful young men to embrace life and its infinite mysteries and adventures.”

Dayton: “We were certainly aware of the Manic Pixie Dream Girl… erm …”

“…trope?” offers Farris.

Dayton: “Yeah. Trope. Quagmire. It’s funny because in the States, there is a big debate about it and it was very satisfying to comment on that without the film being overwhelmed by it.”

For 29-year-old Kazan, who was inspired to write Ruby Sparks after mistaking a mannequin in a dumpster for a murder victim (“I thought it was a dead body and that made me think of Pygmalion and the sculptor in his studio who turns his head and thinks he sees his creation moving”), the film’s gender politics inadvertently came to the fore because she was shining a spotlight on what it means to create a character.

“To me, it had a lot more to do with what we do to each other when we’re in love. When we meet someone, we tend to automatically put them in a box in terms of the way they look, the way they talk, the way they dress; we make a lot of assumptions and then, later on, a more complicated picture emerges and you have to kind of wrestle with that first image and eventually accept the person for who they are.”

In keeping with the film’s meta dimension, that kind of dilemma was something that Kazan found herself grappling with as the film’s writer and star. As the daughter of screenwriter parents (and the granddaughter of On the Waterfront director Elia Kazan), she was brought up to believe that you shouldn’t mess with what’s on the page. “But since doing our movie, I’ve totally revamped my feelings on that. There were scenes (where) I felt so strongly that what we had originally was going to work, but when we came to perform it – even though I’d written it – I was like, ‘This isn’t right at all.’ So now I’ve become the writer’s worst nightmare.”

On the plus side, she seems to be a director’s dream. Dayton has nothing but praise for her commitment to both disciplines, and was particularly impressed at her ability to pen rewrites for Ruby Sparks during the scene changes of a Broadway production of Angels in America in which the increasingly in-demand actress was starring.

Faris, meanwhile, reckons that their desire to do justice to Kazan’s script and the cast’s performances was, in the end, the biggest pressure they felt as filmmakers. “I think I feel more responsibility to that than I do to following up a successful movie.” Spoken like a true artist.

• Ruby Sparks is in cinemas from 12 October.