Chef Carlos Cruz of Saint Lou's Assembly Credit: Julia Thiel

“Land caviar” is a common nickname for tonburi—the seed of a plant known as kochia or burning bush, among other names. In Japan, the seeds are considered a delicacy similar to caviar and used as a garnish for sushi; in China they’re used in traditional medicine. Chef Carlos Cruz of Saint Lou’s Assembly, challenged by John Kirchner of GT Prime to create a dish with tonburi, says, “It wasn’t what I expected. There’s not that much flavor to it.”

“Everyone talks about how it’s like caviar, it pops in your mouth,” Cruz says. “It does pop in your mouth just a little, but it’s not extreme.” The tiny seeds are dried and boiled before being placed in jars and sold commercially; they’re typically served as is, but Cruz went to great lengths to bring out their flavor. “I’ve tried toasting it, fermenting it, even blooming it,” he says. Cruz compares the smell to tea. What little flavor there is, he says, is grassy and earthy.

Not all the experiments were successful right away. Dehydrated tonburi “didn’t look so hot,” Cruz says. “It was totally weird, like plastic. You couldn’t chew on it—it would stick to your teeth.” But once he toasted it in a saute pan, “it started popping like popcorn. It gave a nice nutty flavor to it.” To ferment the tonburi, Cruz vacuum-sealed it and cooked it sous vide for three days at 90 degrees, which made the seeds start to sprout. Then he prepared risotto with a stock from roasted lamb bones and added the fermented tonburi to it.

“I wanted to use bold flavors with [the tonburi],” Cruz says, and “lamb fat goes very well with it.” He seared lamb shoulder as well, serving it with the risotto and dehydrated tonburi, plus two more preparations: tonburi rice crackers and tonburi chimichurri sauce. For the first he cooked the seeds with rice and water, spread the mixture onto a silicone mat, and dehydrated it, then deep-fried the crackers so they’d puff up like chicharrones. The chimichurri sauce, in addition to tonburi, involves vinegar, salt, pickled ramps, parsley, and cilantro. “That added a lot of depth and flavor; the tonburi itself pops,” Cruz says. The last element of the dish was a sea urchin espuma (aka foam), which added salinity and a contrasting texture. Tasting it, Cruz noted, ” This is actually really good. I’m pretty surprised with myself.”

Carlos Cruz’s dish of lamb shoulder, risotto, and tonburi four waysCredit: Julia Thiel

Who’s next:

Cruz has challenged Gabino “Bino” Ottoman, chef at the Ruin Daily, to create a dish with tamarillo, a fruit native to South America that’s part of the nightshade family.