Charred Tuna Sashimi With Brown, Buttered Onion

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Charred Tuna Sashimi with Brown Buttered Onions

by Chef Tu David Phu

This is the perfect recipe to impress your friends, but with little to no effort. It’s also a great excuse to buy a kitchen torch…or befriend a flame-loving friend who just might have one laying around. The ingredients really speak for themselves in this dish, so make sure to use sushi-grade tuna for the freshest flavor and optimal texture. The high-quality fish paired with the luscious brown butter onions makes for a real show-stopper.


  • Skillet
  • BlowTorch
  • 1/4 lb fresh tuna, center cut loin
  • 1 whole onion
  • 1/2 lemon
  • 3 tbsp salt
  • 1/2 lb butter
  • 1/4 c. neutral frying oil
  • Togarashi for garnish

Prepare Brown Buttered Onions

  • Peel and halve onions. Then, very carefully, slice razor thin using a mandolin.
  • Preheat skillet with oil. Then start browning onions, stirring and folding often. This can take a while so be patient!
  • Once onions start to brown, add butter and brown butter with onion.
  • Season with a few pinches of salt. Be sure to taste it!

Prepare Tuna

  • Remove tuna skin and slice into sashimi-sized slices.
  • Tip: cut against the grain.

Assemble & Your Charred Tuna Sashimi 

  • Season tuna with salt and dress tuna with fresh squeeze of lemon.
  • Garnish with rosettes of warm, brown-buttered onions.
  • Drizzle brown butter from skillet.
  • Using a blowtorch, brûlée tuna for 5 seconds on all sides.
  • Generously sprinkle togarashi seasoning.
  • Serve!

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