Sitting in a cozy Upper East Side restaurant, 25-year-old Deborah Feldman stashes her copy of “The Girl With the Dragon Tattoo” in her handbag and greets the chef, who’s come out to say hello. Clad in a miniskirt, semi-sheer sweater and cowboy boots, this confident, stylish young woman seems every bit your typical New Yorker. Then she begins to talk about her background.

Until two years ago, Feldman was part of the ultra-conservative Hasidic Satmar community based in Williamsburg. Abandoned by a mother who left the faith and a father who was mentally disabled, she was taken in by her grandparents, who brought her up to be a quiet, obedient, God-fearing woman who would get married in her teens and start a large family right away.

But Feldman had other plans.

In her memoir, “Unorthodox: The Scandalous Rejection of My Hasidic Roots,” out Feb. 14, she chronicles her oppressive upbringing and arranged marriage.

At 23, emboldened by classes at Sarah Lawrence College, she left her husband and the community for good — taking her 3-year-old son with her.

Feldman recently discussed her experiences with The Post over (very nonkosher) crabcake sandwiches and Key lime tarts: “I think I love eating out more than most people,” she says, “because I was never allowed to do it. Women aren’t allowed to eat out.”

The Post: From a very early age, Hasidic girls are expected to wear skirts and shirts that cover them down to their wrists and ankles. But during your adolescence the law became even more restrictive.

Feldman: When I was 11, they changed the clothing rules. You used to be able to wear a long-sleeve, high-neck T-shirt. Now you can only wear high-neck blouses, with woven fabrics, because their theory is that woven fabrics don’t cling. T-shirts show boobs.

If you had a curvy body, then there was something wrong with you. No matter what I wore, the school principal always had a problem with me, because I’m a little Kardashian-esque and I developed young. My principal would walk by and slap me on the ass and be like, “Your skirt shows too much.”

Every summer, starting when you were 8, you were sent to a Hasidic summer camp upstate; can you describe the bathing suit you had to wear?

Picture this really shiny nylon fabric and thick, floppy, long sleeves, and pants covered with an extra layer of material to make it look like a skirt. Ridiculous. I remember the sound it would make when the girls walked around the pool with the wet bathing costumes, the slapping sound against the backs of their thighs. So awful.

At 17, your grandparents arranged to marry you to a local man, as you were already on the old end of marriageable and, with absentee parents, you made a less-than-perfect prospect. You met him only once before the wedding.

When I met him, I warned him. I said, “I have my opinions, you might not be able to handle that.” But he was famous for getting along with everyone. So he said, “No, I can handle you.” He wasn’t ready to handle me at all! After we got married, and I had my books in the house, he didn’t mention them. He tolerated them. But he would tell his mother everything.

Satmar women are expected to shave their heads and wear wigs once they get married. But you didn’t keep up the first part.

I only shaved my head for a year. I just got tired of seeing my head like that in the mirror. It felt really depressing — like an embarrassing secret. I have a hard time cutting my hair now, because I remember how long it took to grow it out the first time.

The subject of sex was a total mystery to both you and your husband. What’s it like to embark on a sexual relationship when you have no idea how it works?

No one ever said the word “sex,” or even “vagina,” to me. We had no clue. We were like, “It’ll work out.” It never worked out. There is an actual rule that you learn before you get married that you are never supposed to look at genitalia. You can’t look at yours, and you can’t look at his. It’s always dark. There’s no hole in the sheet, but it’s pitch dark and there’s no looking and there’s a lot of fumbling around, and you’re wearing your nightgown rolled up to your waist. There’s no boob touching. Mine were totally wasted! There is no oral sex. After the first time, you have to call a rabbi and he asks the man questions — did this happen? And he declares you either unclean, or not yet consummated. Once you’re consummated, you’re unclean, because you bled. So after the first time, your honeymoon is a no-sex period.

For two weeks every month, he can’t touch you. He can’t hand you a glass, even if your fingers don’t touch. He has to put it down on the table and then you pick it up. Secondary contact can’t happen. If you’re sitting on a sofa, you have a divider between you. It makes you feel so gross. You feel like this animal in the room. If there’s a question about your period, you take the underwear and put it in a zip-lock bag, and give it to your husband. He takes it to the synagogue and pushes it into this special window and the rabbi looks at it and pronounces it kosher or nonkosher. It’s so disgusting.

You say there were many ways in which you felt like your safety was not protected, because of the Hasidic reliance on faith.

I remember always being in the front seat of a car when I was a kid, without a seat belt. It comes from this idea that you have so much faith that you don’t really have to do anything because God will protect you. It’s a very lackadaisical attitude toward health and safety. No one ever took me to a doctor.

I was taught to believe that outsiders hated me. That if I talked to someone [non-Hasidic], I risked getting kidnapped and chopped into pieces. Never, ever talk to an outsider. Not even a policeman. Which is why what happened to Leiby Kletzky [the 8 year-old Borough Park boy who was brutally murdered in July; an Orthodox man is currently facing charges for his murder] could have happened to me. I was taught to trust a Jewish person over someone wearing a cop uniform. If I got lost, to find a Hasid. There was this old man on my street who, every day on my way to school, would be sitting on this bench, and would call out to me and offer me candy. I told my grandfather, and he said, “Well, he’s older than you, so you have to talk to him out of respect.” The guy was, like, a pedophile. And we were taught to respect him.

What was your feeling about the recent news story about the segregated B110 bus in Williamsburg?

I rode that bus countless times in my childhood. It never bothered me to ride in the back. To be honest, I didn’t want to sit anywhere near those men. Those men are scary; they’re not trained in civility. They’re terrified of what would happen if the genders weren’t segregated. They think of lust as this uncontrollable, wild impulse.

That’s what was going through my head [at age 12] when [a sexual assault] happened in the basement with my [male] cousin: It’s obviously all your fault and not his, and you need to keep quiet about it.

As a girl, you attended a single-sex religious school where you say girls were not encouraged to learn English well. But you would sneak books like “Anne of Green Gables” and “Pride and Prejudice” right into the classroom!

I did some brazen things. I got this cheap paperback, I think it was “Little Women,” and tore off the covers so you couldn’t see what it was, and I would insert it in my Hebrew textbook. People thought I was weird.

There’s an explicit rule about women not reading the Hebrew text of the Talmud. I went and bought a section. I was worried about the cashier ringing some alarm under the desk! I was like, “It’s for my cousin. I don’t even know what it is.”

How and when did you finally decide to leave?

I had been taking classes at Sarah Lawrence College — one was this history class, where the teacher was exploring memoirs. It brought to life this idea that one person can make history. And I thought, “I might be able to make a mark or have my voice heard.” And I had all these people around me there who supported me. I asked my college friends, “If I leave, would you really have my back? I have no one.” I have this one friend who said, “I promise, you will never fall because I will always be here to catch you.” And she kept her promise. I left on the basis of that promise.

And then I got into this really bad car accident on NJ 80. My tires were thin, and I was driving fast. My car flipped over three times. I was convinced I was going to die. And there was no way I was going to waste another minute of life.

My husband rushed to see me in the hospital. I’d been talking to him about changing those tires for six months, and he wouldn’t. I said, “Our son could have been in that car.” When I left the hospital, I told him, “I’m going to go stay with my mom for a bit when I get out.” I packed up my stuff while he was at work, and I went to stay with my friend from Sarah Lawrence. While I was there, I was like, “This is it. I’m not going back.”

Knowing that your grandparents and other relatives might well be ostracized on your behalf if you left, did that make it harder to leave?

It wasn’t an easy decision for me. I was thinking, “Can I make myself live this life for their sake?” And I couldn’t. I don’t want to cause them any pain. But I couldn’t justify staying for them. Now, I am a pariah. It’s over. I’ll still go to Williamsburg, to have brunch with [non-Hasidic] friends and walk around. No one recognizes me.

You divorced your husband, who still lives in the Hasidic community in Airmont, NY — what is your arrangement regarding your son?

We have primary modified joint custody, which means I get the last word. My five-year-old son spends every Shabbat with his father. My ex-husband is so much less religious now. He cut his beard short, he wears jeans. It’s because there’s no room for divorced people in the community, so you’re relegated to the fringe. People ask if I would get back together with my ex. It’s a reasonable question; we were married. But I never chose to be married. He’s a stranger to me. I just happen to have a child with him.

How did your relatives react to the news that you were publishing a book?

My family started sending me hate mail, really bad. They want me to commit suicide. They’ve got my grave ready. [“R U ready to CROKE [sic]” reads one e-mail she shared with The Post. “We are most definitely going to rejoice in your misery,” another declares.]

So I’m very careful. My doorbell doesn’t have my name on it. But I think the book is a protection in this situation, because [my relatives] are terrified of having their actions become public. So it’s an insurance policy, in a way. There’s a reason why Hasidic people in New York get away with so much. There’s this sort of tacit arrangement: They don’t do anything the media can criticize.

Over the past 10 or 20 years [the Hasidic community] has gone from being extreme to being ultra-extreme. They’ve passed more laws from out of nowhere, limiting women — there’s a rule that women can’t be on the street after a certain hour. That was new when I was growing up. We hear all these stories about Muslim extremists; how is this any better? This is just another example of extreme fundamentalism.

Do you see some signs of hope now, because outside influences are trickling into the cloistered community?

The neighborhood has changed drastically since I left. The hipsters came in the ’90s. And computers hit in a big way. Smartphones. Internet access. Now you can’t keep people from accessing information. It’s weakening the community’s hold over their own. It used to be that one person would leave, and then another 10 years later. It was always a big-deal scandal. This year, I went to a Thanksgiving dinner for people who are trying to get out, hosted by an organization called Footsteps, which helps people adjust to mainstream society. There were 350 people at this dinner. They had to rent out a loft in SoHo.

What’s your dating life like now?

Part of me is like, “I can’t date anybody. No one will [understand] me. I have a kid and I’m 25.” But there’s a man I met in New Orleans. He has his life there, and I have mine here. On paper, we don’t make sense at all — he’s Irish Catholic, he grew up in the backwoods. But he’s the only person I ever met that never made me feel weird about my life. He saw me for me. I thought that was impossible.