Make a creamy soup without a heavy cream or flour: That was the challenge for Scott Leibfried when developing the menu for the health-conscious fast-casual restaurant ReViVer.

The resulting cauliflower soup has been a vegetarian staple on the menu since ReViVer first opened in Hell’s Kitchen more than two years ago (a second location recently opened in Flatiron).

“It’s become very popular amongst vegetarians for sure, but non-vegetarians have really gravitated toward it, too,” said Leibfried, executive chef and co-founder of ReViVer. “It’s something you might expect to see in a much higher-end restaurant, and get charged much more for it than we do.”

The soup gets its creaminess and thickness not from fat or flour, but skim milk, cannellini beans and potatoes. Leibfried tops it with extra virgin olive oil, toasted almonds and scallions.

“Olive oil as a garnish is something I’ve always done in my cooking,” the chef said. “I think it’s a unique way to import really unique flavors. The toasted almonds are a nice enhancement to the cauliflower in a nice crispy texture.”

Like other dishes on the ReViVer menu, the soup doesn’t feature refined sugar, processed flour, artificial ingredients or excessive fat. Instead, the restaurant prepares its spreads and salad dressings in-house and uses 100% whole wheat flatbreads.

“We’re more resourceful in what we use to get great tasting food,” Leibfried said. “Where a lot of restaurants might add more butter or salt, we’re more resourceful in getting flavor.”

The menu items also feature a precise balance of carbohydrates, fats and proteins — so for this cauliflower soup recipe, a scale is needed to measure out some of the ingredients in grams.

“That has to do with the nutritional promise that we make,” Leibfried said of the recipe.

The chef recommends buying fresh cauliflower, not frozen — “You get a lot of flavor out of the core, not just the outside of the cauliflower” — and making time for the simmering process.

“There is a certain amount of tenderness and simmering that will make it taste best,” he said.