For me, every book feels like the first book, enthuses the award-winning American writer, Nathan Englander. His latest novel, kaddish.com comes out almost 20 years to the day after his bestselling first book, For the Relief of Unbearable Urges, a bold, tragi-comic collection of short stories, rooted in Jewish history and Orthodox life.

“I’m so thankful to still be a fiction writer, as much as I drive my wife nuts,” says the fast-talking author, over the phone from his Brooklyn home. “I get excited about each book, even though I become an overwhelmed, torturous person who sweats over a comma. But I want each book to be the book.”

Englander admits that kaddish.com is his most Jewish book “by infinity.” Its protagonist, Larry, is an atheist in a family of Orthodox Jews. When his father dies, it is incumbent on him to recite the Kaddish every day for eleven months but to the horror and dismay of his sister, he refuses, putting the fate of their father’s soul at risk. To appease her, Larry hatches a plan and hires a stranger through a website called kaddish.com to recite the prayer instead of him and, by doing so, guide his father’s soul safely to rest.

It is a funny, fast-paced, irreverent yet affectionate tale about family, faith and religiosity. Acutely observed, it skilfully captures the tensions between tradition and modernity. Writing it was a wonderful experience, he says. “I don’t know what it’ll do in the world, but I feel close to this book on all fronts.”

Born into an Orthodox family, Englander grew up in West Hempstead, Long Island, and studied in yeshivah until he went to college. He was observant and “so well behaved” but would get into trouble.

“I wasn’t smoking weed or cutting class, but I’d get thrown out by the rabbis for asking questions.” He would challenge the concept of God’s omnipresence. “Part of what they’d asked us was this notion to believe in God who knows everything that everyone is feeling and doing. I felt that’s a very big ask of a little kid to believe that God can know all that.”

Englander fought to be able to study at a secular university and graduated from the State University of New York at Binghamton. In his junior year, he went to Jerusalem —his first trip outside the US and an experience that would prove to be transformative. It was here that he became “radically secular.” Until then, all he had known were Orthodox people: coming across secular Jews was a cultural shock. “To show up there and see Jerusalem as a real place —for someone raised religious, that contrast was explosive to me.” And part of kaddish.com is set in Jerusalem and Englander’s portrayal of the city — a place where he chose to live for five years in the 1990s —is highly evocative.

“I can remember running on the treadmill and staring at the old city walls,” he recalls. “As someone interested in story, all those differing — and bizarre — narratives really shaped me. And it is a city full of promise. How many people go there searching for something? I may have gone there religious but that’s where I took off my yarmulke.”

As much as his previous novel, Dinner at the Centre of the Earth, took Englander far from the imagined worlds where he started — it explores the peace process, or lack of, between the Israelis and the Palestinians — kaddish.com brought him right back to where he began, in particular exploring the boundary between the sacred and profane.

“This line really obsesses me and the crossing of it drives so much of the world. I grew up in a religious black-and-white world with much of it driven by an understanding of ethics and I think I’m just fascinated that the world doesn’t work that way.”

Englander also began to think about the customs and rituals of Jewish death and mourning, as it is ten years since his father died. “It’s back to those rules. It’s always interesting to me when friends, whether they grew up religious or not, take on saying Kaddish three times a day. It’s a huge, huge undertaking but, for a religious person, the expectation that it wouldn’t be said really would put someone’s soul in danger.”

He asked himself what the modern response would be if people were to pay for others to say Kaddish and says he realised that there would probably be a website. From a halachic perspective, he explains, it is acceptable for someone to say the mourner’s prayer on someone else’s behalf if you do not want to do it yourself: “It really is ok.”

Although it has been two decades since Englander became secular, he jokes that friends are waiting for him to return to Orthodoxy. “If I say that I’m not religious at events, everybody rolls their eyes,” he laughs. When he and Jonathan Safran Foer were promoting their New American Haggadah, for which Englander wrote a translation of the original text, they would include it as part of their routine.

“After describing myself as an atheist, I’d then read a portion from the Haggadah on stage and Safran Foer would turn to audiences and ask, ‘Have you ever seen a more religious man?!’ I think my wife is terrified that she’s going to come home one day and I’m going to be fully Chasidic.”

Sometimes, teasing makes stories, he says. It led Englander to wonder what would happen if he did switch back and as a result, Larry is later reborn as Reb Shuli. “I see how much I’m interested in identity and change and what these shifts mean for people. I don’t think I ever moved past the fact that I grew up in one world and now live in another and my brain plays both sides of everything.”

Englander’s website appears entirely plausible; it seeks to make a match between the deceased and a young Torah scholar who commits to the task. In the novel, Larry likens it to, “a JDate for the dead.” Does such a site exist?

Now, yes, says Englander. “When I finished the book, I was very happy that there isn’t one called kaddish.com. I’m still trying to find the name.” But he did come across a similar domain, kaddishcom.com. “I don’t know what they think will go there,” he says laughing again. “But man, did I want to buy that site!”

Englander has discovered that much of his fiction has turned out to be true, unbeknown to him. One specific example, he says, occurred in his first book. In the title story, his character gets special dispensation from his rabbi to see a prostitute to relieve his unbearable urges.

“Someone read it and brought me the direct line from the gemara about unbearable urges. It blew my mind that it’s there.”

Although Larry is not based on anyone in particular Englander stresses that, for him, characters and their environment have to feel entirely credible. He tries hard to impart this to his students at NYU where he is Distinguished Writer-in-Residence.

“It’s so important to me. Yes, it’s a fictional reality, it’s made up, but it really needs to build its own reality.

“When you start out, characters aren’t real but that’s the whole point of drafting and redrafting. You write until, basically, they take shape and you’re just following along.”

When Englander began writing, he disliked being referred to as a Jewish writer. “It’s the identity thing, it came from a point of pride. I said I was an American writer: I’m an American, my parents and grandparents were born here.

“This idea that, as a New Yorker, I have to be a certain type of writer was about objectification. I was really defensive about it for years.”

But now, with rising antisemitism in the US, from that same point of pride he makes it clear that he is a Jewish, American writer.

“I guess I was also fighting for the universality of story and my belief that if a story is functioning, it’s universal,” he continues.

“So, with this book, I just think, read it like science fiction about Jews. If you can read science fiction, you can surely read about Jews.”

Englander does not believe in writer’s block and the Pulitzer shortlisted author (for What We Talk About When We Talk About Anne Frank) is a self-confessed workaholic.

He has, however, embraced the changes required since becoming a parent.

“Wanting and being able to be at home has been really good for me. I found that, instead of feeling like I don’t have enough time, it’s been so creatively rich.”

He has his second play in the works among other projects. I ask if there has been any discussion about adapting kaddish.com into a film. He claims not to know.

“That would be really fun, but they don’t tell me anything until it’s over. But we could play cast-the-rabbi.”

kaddish.com by Nathan Englander is published by Weidenfeld & Nicolson.