Celebrity chef leaves one iconic ingredient out of her French cooking and diners can't tell

For a French chef, cooking without butter might sound like culinary sacrilege. But for Olivia Ostrow, it's part of the job.

The Paris-born restaurateur and contestant on Food Network's "24 in 24: Last Chef Standing" serves French-Mediterranean cuisine at Maison Ostrow, her kosher restaurant in South Florida, where the meat-based menu means dairy cannot be mixed into dishes.

That presents an unusual challenge for a chef working in a cuisine famous for its reliance on butter, cream and cheese.

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"Can you really make great French food without butter? Yes and no," Ostrow told Fox News Digital.

One solution comes from another ingredient long associated with .

"There's a little secret called duck fat," she said.

But Ostrow and her culinary team have also developed their own non-dairy versions of ingredients that would otherwise be off-limits.

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"We started making our cheese and we started our butter," she said.

Maison Ostrow serves its house-made baguettes with roughly seven varieties of its butter alternative, Ostrow said, including truffle, spicy and Provençal versions.

Diners are sometimes surprised when they learn what they're eating isn't traditional butter, Ostrow said.

Yet butter isn't necessarily the toughest obstacle in adapting French cuisine to kosher requirements.

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"Desserts," Ostrow said when asked about the toughest dish to recreate for kosher palates. "It's hard."

Her team developed an alternative to mascarpone for a tableside take on tiramisu, she said. Steak au poivre posed another challenge because the traditional peppercorn sauce is typically creamy.

Not every attempt succeeds.

If a creation doesn't live up to what Ostrow believes diners would receive at a traditional in Paris, she said she doesn't want it on the table.

The experimentation comes with another cost: time.

Ostrow said her chefs spend hours working on sauces, dressings and substitutes, including developing something that tastes like blue cheese that isn't made with dairy.

Another restaurateur examining her books might question the restaurant's labor expenses, she acknowledged.

"Yeah, my labor's a little high because we work a little harder," she said.

Kosher cooking has also taken on deeper significance for Ostrow.

She opened her first glatt kosher restaurant about a month before the Oct. 7, 2023, Hamas attacks in Israel. Jewish identity had long been central to her life, but Ostrow said the aftermath strengthened her resolve to use her growing restaurant business as a public expression of that identity.

"I did not feel that I needed to go into hiding," she sa