Thursday is not technically Shabbat, but on the evening of Nov. 10, more than 100 millennials and members of Gen Z packed into a loft in SoHo to observe it anyway.

The Jewish sabbath begins at sundown on Friday and ends at sundown Saturday, but the host of this event, the jewelry designer Susan Alexandra, really wanted Matt Green to preside over the gathering. He spends every Friday at Congregation Beth Elohim in the Park Slope neighborhood of Brooklyn, where he is assistant rabbi, so Ms. Alexandra opted to hold the dinner a day early.

“It’s a little weird that it’s not on a Friday,” Rabbi Green said, “but whatever gets people excited about Shabbat works for me.”

Some attendees came dressed for the occasion, which was held at Haven’s Kitchen, a cooking school: One person wore a “Fiddler on the Roof” T-shirt with a skirt and combat boots. Another sported a worn Zabar’s baseball hat. Lindsey Solomon, Ms. Alexandra’s publicist, who is 30, dug out a kipa he had acquired at a bar mitzvah in middle school.

Chopped liver and brisket were served, and people wished each other a Shabbat Shalom, toasting “l’chaim!” with canned botanical-infused vodka spritzes.

Rabbi Green led the blessings over the candle, wine and challah, and smiled widely at the crowd. “We are all trying to figure out how to be Jews in the 21st century,” he said. “And this is it.”

An Antidote to Antisemitism

Across the country, more young people — Jewish and not — seem to be celebrating Shabbat. Some see it as a natural way to unplug — religious Jews typically avoid electronics on the Sabbath, and many nonobservant Jews opt to put their phones away so they can be present — and connect with family and friends.

It’s also an opportunity to support and celebrate Jewish culture after a recent surge in antisemitism. The Anti-Defamation League recorded more incidents of harassment, vandalism or violence toward Jews in 2021 than any year since it started counting in 1979.

“It’s actually been four years since the Pittsburgh synagogue shooting,” Rabbi Green said, referring to the 2018 massacre in which 11 people were killed. “Ever since then people have been holding on tighter to their traditions.”

Recent incidents include antisemitic tweets by Kanye West and the brief suspension of the Brooklyn Nets basketball player Kyrie Irving for tweeting a link to a documentary that denies the Holocaust. Former President Donald J. Trump dined last week with Mr. West and Nick Fuentes, a Holocaust denier and white supremacist, which Mr. Trump’s Jewish allies denounced.

Ms. Alexandra, 36, said she believed that people were more interested in coming together for Shabbat because of recent events. “I think there is a solidarity,” she said. “People want to show that they are proud of being Jewish and they believe in the spirit of Judaism.”

She said she had seen more sales of a Star of David necklace in recent months, even though it’s an older piece and the company did not advertise it. She debuted a new line of Judaica at her Shabbat dinner.

Erin Allweiss, a founder of No. 29 Communications, said she has been reconsidering her Jewish identity. “As we are watching antisemitism come to an uncomfortable rise,” she said, “we need to do more.” And, for her, that includes marking the Sabbath.

Many are observing Shabbat not just occasionally, but every Friday, something that historically only observant Jews have done.

OneTable is an organization that gives Jews between the ages of 21 and 39, who aren’t in college, money to host a Shabbat dinner ($300 if it’s open to the public; $100 if it’s invitation only). In 2019, before the pandemic, it helped fund 9,000 dinners. In 2022, it has contributed to more than 20,000.

There is, naturally, Shabbat TikTok: Sarah Haskell, @thatrelatablejew, amassed over 100,000 views on a post walking her followers through her first time hosting a Shabbat meal. She has also posted about hosting anxiety.

Chaya Bindell, a founder of Trybe, a Los Angeles start-up that creates Shabbat experiences, said she believed that the increase in popularity was also about people craving connection, especially after pandemic isolation. In 2016, Trybe would host about 80 people per event, she said. Now it’s about 300.

“Shabbat is an ancient ritual, but it’s really a simple and genius community building tool,” she said. “Shabbat provides an answer to a deep human need. You stop working, share a meal with family or chosen family, put away your phones, look each other in the eyes, connect and talk.”

Partying Till Sunrise

The ritual builds community with non-Jews too. Shay O’Brien, a Ph.D. student studying sociology at Princeton, attended her first Shabbat dinner at a friend’s home on the Lower East Side at the beginning of November. “It definitely felt more special than a regular dinner,” said Ms. O’Brien, 32.

And: “Someone made homemade challah bread that I am still thinking about.”

Marie-Salomé Peyronnel, a writer and curator in Brooklyn, has hosted Shabbat meals in New York City for a decade. Now, she said, more of her friends want to join. She believes it’s very much about the food.

“I think there is a huge movement of food people reviving Jewish traditions,” Ms. Peyronnel said. “There are so many people creating babka and challah and mandel bread.”

On a recent Friday, she and her husband, Marc Azoulay, 38, the studio director and producer for the French artist JR, made a spread of Moroccan fish and a cucumber salad with sumac, mint and olive oil. Ms. Peyronnel, 36, and Mr. Azoulay, 38, own HaYom, a company that sells Jewish art.

Trybe, Ms. Bindell’s company, is known for hosting events mostly in Los Angeles but also around the country, either in a private home or event venue. Attendees sit on Moroccan rugs, lean on pillows or poufs, and eat on low tables filled with platters of food; some dinners draw more than 100 people. The events may include acoustic music, guided meditations, poetry and D.J.s. Some evenings last until sunrise.

Daniella Kallmeyer, 36, a South African-born fashion designer, sometimes hosts a Shabbat dinner that celebrates the Jewish queer community in New York City, where she lives.

She started hosting 10 years ago when she pulled up folding chairs around a card table. The demand has grown so much that this year she rented a loft on the Lower East Side that can double as her showroom and dining room.

On a recent Friday night, more than 40 people gathered for a dinner of red snapper, roasted vegetables and homemade challah. “It doesn’t matter if she knows you,” said Ariel Wengroff, 33, who works in global marketing and communications. “You are always welcome at Daniella’s table.”

‘It Works Because It’s Simple’

When Jeffrey Albaum, 25, who works in real estate investment, moved to Austin, Texas, a year ago, he decided to host Shabbat dinners using OneTable. “There are a lot of people who have recently moved here and are new to the city, so this was a great way to meet people,” he said. A year ago, he would host five to 10 people. Now he’s hosting more than 50.

“It’s not a sit-down, white-tablecloth type of thing,” he said. His roommate makes a pot of meatballs, and they serve them on paper plates with plastic cutlery.

Ms. Allweiss, 39, started hosting her own dinners this year. Her strategy is to team up with veterans. At the end of October she hosted a dinner with a 60-year-old friend. They each invited about a dozen friends from their generations.

“It was so moving,” Ms. Allweiss said. “Everybody put down their phones, and we went around the room and said something that has been on our minds.”

“Shabbat is something I now want to do as much as possible,” she added.

Ms. Bindell said it had become a “hard” behavior. “It works because it’s simple,” she said. “You have dinner together, and you do it consistently, every Friday night.”