His is one of the few restaurants in Oslo that serves the steaks from the upper flanks of minkes that Norwegian whalers kill in their hundreds every summer.
Siva moved with his family from Sri Lanka to Norway 23 years ago and says he doesn't get many complaints, although the most vociferous feedback on the restaurant's signature dish comes from New Zealanders.
"They really give us a hard time on Facebook," he says.
Those Norwegians who partake tend to eat it at home, most supermarkets sell it frozen, and during the summer it can be bought fresh and is put on the barbecue.
Eating whale can provoke an outcry, depending on who's doing it. Earlier this year, royal relative Pippa Middleton was criticised by animal rights groups for "promoting the cruel and unnecessary whaling industry" after writing about eating smoked whale carpaccio while at a lodge in Norway's northwest.
At the historic city of Bergen further south, smoked whale was selling last month for more than NZ$100 a kg at the waterfront fish markets, popular with whale -- but the sight of a drawing of a happy-looking whale to promote the meat was too much for one young American woman who said "that's disgusting".
Norway broke from the international ban on whaling in 1993 and has been increasing its catch since, last year killing 729 of the mammals which can grow up to 10m long. Females are the largest and grow to about 8m long and weigh four to five tonnes.
Greenpeace Norway spokesman Martin Norman says whaling was an industry that "clearly belongs to the past".
While his organisation was satisfied the minke species was not under direct threat, harpooning the whales was a brutal way of killing an animal. Norway, Japan and Iceland were by themselves in defying the United Nations.
"Norwegians don't know how much it takes away their credibility on other issues in the UN. How can we expect North Korea to follow the UN decisions when they don't like it when we don't follow them when we don't like it."
Whaling dates back to the Viking days around the 900s and Norman said his country had a bad record of decimating whale stocks in its more recent past.
It had been an important source of food during the austere post-World War II years but was out of place in modern Norway.
"Young people don't tend to eat it," Norman said.
But another Norwegian environmental group takes the opposite view.
Lars Haltbrekken of the Naturvernforbundet (Friends of the Earth Norway) says his organisation objected to hunting minke when the stocks were low in the 1980s but once they recovered changed its stance.
"We support the whale hunt because we don't look at it as any different from hunting moose or reindeer or catching fish, as long as we have enough moose in our forests, enough reindeer in our mountains. With whaling, as long as there is enough of it, we can hunt it as food."
Whale meat on the menu at Nilsen Spiseri restaurant in Oslo, Norway.
He said the international community should be more concerned about other environmental threats.
"If people want to get upset about Norway it is the oil and gas production that is the biggest environmental problem," Haltbrekken said.
The Sami people -- the original inhabitants of Norway's north, also wanted the right to keep eating whale.
The president of the Sami Parliament, Aili Keskitalo, said whale was a traditional food.
"We think that natural resources should be managed," she told the Herald at the Sami Parliament in Karasjok. "We are a nature people so we eat our animals, we don't buy them in the shop.
"In our culture it's the difference between being a human and being an animal -- we do not humanise our animals. Of course the whales as a resource should be managed based on statistics, the resource and knowledge, not because some animal protection group finds them cute or more worthy than other animals."
Back at the Nilsen Spiseri, a group of mainly Australian lads on a Kontiki trip were tucking in to whale steaks part way through a 22-day Baltic escapade.
The verdict from Luke: "It was pretty much like a rump steak at home but a bit dry." For Mathew, the NZ$40 whale with potatoes and greens at the restaurant was his second helping of whale meat for the day after a slither on a pricey tasting platter at the waterfront. He reckoned he'd tried something similar in South America: "It tasted like alpaca."
Grant Bradley travelled in Norway with the help of a media grant from the Royal Norwegian Embassy.
