It’s a sunny Sunday morning in a middle-American kitchen. Walt wants some good, old-fashioned blueberry toast, and his chirpy wife, Barb, is only too happy to oblige. When she serves it to him, though, there’s a problem: he claims he asked for pancakes. With that minor discrepancy, the blissful facade of Blueberry Toast begins to splinter. “Perhaps we should start saying what we think,” suggests Barb. “That’s no way to live,” Walt replies. By the time this highly concentrated 70-minute play is over, every spotless surface is spattered with blood.

This is the sort of heightened comic horror for which the 32-year-old Texan Mary Laws is quickly becoming renowned. “It’s always where I end up,” she admits over coffee in Soho theatre’s bar. She is one of two female playwrights (the other is Polly Stenham) with a writing credit on The Neon Demon, a stylish fashionista horror movie from Nicolas Winding Refn (Drive), and she has just finished her third season on the AMC series Preacher, the wilfully outrageous comic-book adaptation with Dominic Cooper as a bad man in search of God. Taught by the playwrights Paula Vogel and Sarah Ruhl, and influenced by everything from Caryl Churchill to The Texas Chainsaw Massacre, Laws bashed out Blueberry Toast in just 48 hours in an airless basement room at Yale six years ago. “I wrote it in a frenzy,” she says. “It just sorta came out.”

The play’s milieu of suffocated suburbia, where the dazzle of kitchen appliances distracts from festering resentments and unspeakable urges, evokes both Douglas Sirk and Blue Velvet. But for all the stylised, gee-whizz banter (Walt and Barb address each other as “dear” eight times on the first page alone), Laws has made a point of setting the play not in the 1950s but now. “That was important because it’s all still happening. This is where I grew up.”

She was raised by her parents, both Methodist pastors, in a pre-fabricated, “master-planned” community near Houston. “People were trying to be perfect but everything was bubbling up under the surface: violence, abuse, drug use, alcoholism. My own home was a happy one but sometimes I was, like, ‘Doesn’t everyone see this?’”

With that in mind, she has written her own surrogate into Blueberry Toast: Barb and Walt’s son, Jack, who is putting on a play with his sister Jill right there in the kitchen. Jack shares Laws’s taste for unorthodox structure – his opus has four acts (“What an odd play,” says his father) – and also her occasional sense of impotence. “He’s a kid so he’s not articulate but everything he sees around him is going into this piece of work. He doesn’t know what the hell to do about it all and that’s my question too. How do you evoke change? I’m from a country that is crying out right now for the cycle to be broken. You can see it in race, gender, everything.”

The #MeToo movement has a particular resonance for Laws. “When I was asked in the past what inspired the play, I’d always talk about where I grew up, or reading Ted Hughes’s great translation of Ovid.” Now, she says, it’s drawn from her own experiences: “Even being able to say that now is a product of seeing women around me being vocal and honest.”

If gender dynamics are improving in the industry, there is still one part of Laws’s life that makes her an outsider: her faith. A producer asked her recently how she could write the material she does and still call herself a Christian. Preacher, after all, shows Christ having sex with a married woman and spawning a line of in-bred descendants, while some of the tamer parts of The Neon Demon feature cannibalism and necrophilia.

“I write what I write because I’m a Christian,” she says. “It informs everything I do. My father always taught me it’s OK to laugh at the things you love. Part of Preacher is about interrogating faith. You can’t do that stuff lightly. For a time the other writers would look at me across the table to see if I was gonna be offended but I never am. I’m happy to write about faith and God and get angry and deep. Let’s pull it all apart and see what’s lasting.”

Her parents are big Preacher fans. “If we have a biblical question, I call them up. My mum sent us long emails about the categories of angels.” They were especially thrilled when Sarah Palin warned Twitter followers away from the show. “Oh, they couldn’t have been prouder. They were, like, ‘Put it on your resumé. You’ve made it now!’”

• Blueberry Toast is at Soho theatre, London, until 30 June. Box office: 020-7478 0100. Preacher returns to AMC on 24 June.