Masa Sasaki has spent the better part of the past four decades honing his craft as one of San Francisco’s most highly respected sushi chefs — most recently at then-Michelin-starred Maruya, and now as the eponymous chef-owner at Sasaki, his handsome $180-a-head omakase spot in the Mission. But early next year, Sasaki will be getting into the burger business, opening a new tuna belly burger restaurant in downtown Oakland. Tentatively slated to open in February 2020 at the previous location of Hutch Bar & Kitchen at 2022 Telegraph Avenue, Masabaga might be the first restaurant of its kind anywhere, Sasaki says.
The idea of opening a burger restaurant centered on toro, the fatty cut of the tuna belly that’s so prized by sushi connoisseurs, is something the chef has been thinking about for years — “I always wanted to do it, for a long long time,” he says. True toro, which comes from the critically overfished bluefin tuna, is, of course, an exceedingly expensive cut, but Sasaki noticed that yellowfin tuna belly, known as haramo in Japanese, was used much less frequently for sushi and sashimi — it’s a cut that’s difficult to prepare well and tends to be too chewy to be enjoyable when eaten raw, Sasaki explains. When the cut is cooked, however, it’s delicious — so juicy and decadent. So Sasaki came up with the idea of breading thick pieces of haramo with panko, frying them like you would a piece of tonkatsu, and then serving it as a sandwich — a “toro” burger.
The problem was that yellowfin belly is almost impossible to procure in large enough quantities to base an entire restaurant on that concept. But Chikara Ono — the East Bay chef and restaurateur behind AS B-Dama, Delage (where Sasaki was the opening chef), and Utzutzu — recently found a Japanese supplier, so the two decided to partner on the project, and Masabaga, named after the Japanese word for burger (“baga”), was born. They debuted the tuna burgers at a recent pop-up at Old Kan Beer Co., and construction on the downtown Oakland space is already underway.
For the restaurant’s signature tuna burgers, Sasaki says he’ll fry the panko-coated belly and serve it on a round burger bun, topped with lettuce and thinly sliced radishes, onions, and mint — all tossed in a housemade shiso vinegar sauce. The fast-casual spot will also serve a regular beef burger, thick and juicy, made with American wagyu beef from Oregon-based Washugyu. It’ll be an American-style burger patty, not the meatloaf-like “baga” that you often find in Japan. “The burger is a burger,” Sasaki says, citing long road trips from his motorcycling hobby as the source of his love of the genre.
Sasaki and Ono are still finalizing the menu and pricing, but they expect the tuna burgers — which might sometimes also be made with bigeye tuna belly or real toro — to be priced at roughly $15 each. The wagyu burgers will cost around $12. There will also be a small selection of sides (including fries) and salads.
In the future, Sasaki says, he might also experiment with other cooked fish sandwiches utilizing the dehydration techniques he uses as a sushi chef. Before Masabaga debuts in February, he expects to host a couple more pop-ups — at Old Kan again, or perhaps at Berkeley Bowl.