But it's here that the manioc root, long the staple food of the Brazilian poor, is making its entree into the elite world of haute gastronomy. And in a country where fine dining has always been synonymous with European food, especially wheat- and sauce-heavy French and Portuguese cuisines, the restaurant's use of this humble, homegrown tuber is the stuff of a culinary insurrection.
Grown in some 80 countries worldwide and known internationally as yuca, cassava or mogo, manioc has its origins in Brazil: It was the main food source for indigenous tribes from across the width and breadth of this giant nation since before the discovery of the New World. Even now, manioc remains an important source of carbohydrates, especially among Brazil's working class, who grind it into a rich, nutty flour or deep-fry it into greasy fries.
Now, top chefs in Brazil and beyond are turning the manioc into The Tuber, unearthing it from its peasant roots and placing it on some of the choicest plates in a defiant, nationalistic gesture.
The Brazilian elite has long tended look down their noses at manioc, which, because it grows wild with no need to be tended, was regarded as a "lazy" crop, says Teresa Corcao, the chef at O Navegador. For her, rehabilitating the manioc and other native plants is key to reclaiming an authentic Brazilian identity particularly as the country, now the world's sixth largest economy, ascends to the international stage.
Corcao has teamed up with chefs from 17 other top Rio restaurants to promote the tuber. In Sao Paulo, Brazil's most famous chef, Alex Atala, is known for serving up classic European dishes using native Brazilian ingredients. And even as far afield as New York, celebrated French-born chef Daniel Boulud, a confirmed Brazilophile, also incorporates Brazilian foods, including manioc, which is also known in Brazil as "aipim."
"In Brazil, we were taught by our colonizers from the very beginning to want to be something else than what we are," said Corcao, who also heads Instituto Maniva, a nongovernmental organization dedicated to raising the profile of manioc. "That attitude is still totally reflected in our diet. We have this incredible food, the manioc, but because it's seen as an 'Indian' food, it's stigmatized.
"So we imported wheat which is of course not native to Brazil and started relying more and more on bread," said Corcao, a 57-year-old self-taught chef who learned the basics of cuisine as a child from the cook in her family's bourgeois Rio home. "The further you were up the social ladder, the less manioc and more bread you ate."
Not anymore, at least not at O Navegador. Housed on the top of the Naval Officers Club in Rio, it was once a traditional restaurant catering to the city's moneyed elite with a menu heavy on European dishes such as filet mignon with pepper sauce or three-cheese ravioli.
In the three decades since she took over the restaurant, Corcao has steered toward something altogether closer to home. On the menu now, a creamy mousse of shrimp and manioc; confit cod and manioc drizzled with aioli sauce; fish of the day with a manioc and banana puree in guise of mashed potatoes.
Manioc in some incarnation, steamed, souffled, stir fried, plays a role in nearly every dish, and not even the desserts here can get away from the versatile root. In the restaurant's version of that Italian standby panna cotta, manioc replaces the namesake "panna," or cream.
Recent research underscores just how healthy, hearty and versatile the manioc is.
The bulbous root, which grows in a bunch beneath a leafy shrub, contains no gluten and is rich in potassium and antioxidants, dense in calories and low in fat. It's also been shown to help prevent certain kinds of cancers, said Joselito Motta, a scientist with Brazil's Embrapa agriculture research agency.
On the downside, it's low in protein, and some varieties contain hydrocyanic acid in doses than can prove harmful if the root is not treated properly before consumption. Still, most domesticated varieties are very low in toxins, said Motta.
The Embrapa manioc facility has a library of some 2,040 varieties of the root, just a fraction of the estimated more than 4,000 varieties once thought to have thrived here. So plentiful and widespread was the manioc that a 17th-century German visitor, naturalist Georg Marcgraf, dubbed the plant "universale Brasiliensium alimentum," Latin for "Brazil's universal food."
Historians suggest the tuber played a crucial role in the colonization of Brazil, providing a reliable food source for early explorers and settlers as they hacked their way deeper into the country's dense jungles. Manioc also played a part in Brazil's more than 200-year-long slave trade, as an important food source on the ships that ferried millions of Africans to Brazil.
From its birthplace in central Brazil, the manioc has spread throughout the tropics and is now widely consumed in South and Central America, as well as Africa and Asia. Nigeria has overtaken Brazil as the world's largest manioc producer, followed by Thailand, where it's often turned into tapioca and served up in sweet bubble teas.
While some 600 million people rely on the root for sustenance, that number could skyrocket in the coming years as global warming pushes temperatures up, Motta predicted. Remarkably drought resistant, manioc could conceivably stave off starvation for millions should other staple crops fail, he said.
In addition, the plant's stalks and leaves have a high protein and mineral content that make them ideal food for livestock.
"The manioc is without a doubt Brazil's most important patrimony, foodwise," said Motta. "But only now are we finally realizing what an important crop it is, and how great its potential for the future is."
As part of her bid to seduce other top chefs to cook with the tuber, Corcao sought out a smaller, more refined variety.
"Baby vegetables are still all the rage, and I myself work with baby carrots, baby peas," she said, as waiters buzzed around her, preparing the dining room for the night's crop of well-heeled diners. "And it struck me: Why not baby manioc?"
On a visit to the farm that supplies the manioc she uses at O Navegador, Corcao found just what she was looking for in the rubbish pile. Having ripped a shrub from the black earth, farmer Otavio Miyata plucked off the hefty roots, Corcao recalled, and jettisoned their underdeveloped siblings along with the stalks and leaves.
"She was like, 'That's it! That's baby manioc,'" said 35-year-old Miyata, a third-generation farmer on a small plot of land some 50 miles (80 kilometers) outside Rio. "For me, that was just trash."
Now, the baby maniocs fetch Miyata ten times the price per pound of their bulkier brethren.
"Manioc was always just poor people's food," said Miyata, as he pan-fried some of the egg-sized baby tubers in butter over the gentlest of flames. "Now, they're becoming almost a luxury."