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Tuna Mayo Onigiri

This easy tuna mayo recipe is more delicious than what you can get at the convenience store in Japan! With the addition of a few secret ingredients, this will be the most flavorful tuna mayo rice ball you've ever had!
Prep Time 30 mins
Cook Time 10 mins
Course Main Course, Snack
Cuisine Japanese
Servings 2
Calories 350 kcal


  • 3 cups cooked short-grain rice
  • 2 sheets of nori seaweed
  • Water
  • Salt

Tuna Mayo Mixture

  • 5 oz canned tuna
  • 1 tsp soy sauce
  • 1/2 tsp dashi powder
  • 3 heaping tbsp Japanese kewpie mayonnaise
  • 1 tsp ketchup


  • Mix the *Tuna Mayo* ingredients and set aside.
  • Tear the nori seaweed along the third perforated line. You should have a 4-inch wide strip. Do the same with the rest of the nori seaweed until you end up with three wide strips. Set aside.
  • Wet hands and add a pinch of salt. Grab a handful of rice and flatten it out.
  • Add a generous heaping of tuna mayo and add a bit more rice onto the filling. Shape the rice into an oval, ensuring that the filling is in the middle of the rice ball.
  • Place the rice ball into your cupped palm. Cup your free hand into and angle and place on top of the rice ball and squeeze gently.
  • Rotate the rice ball about 120 degrees (so that the tip of the triangle is pointed up), and squeeze again. Continue to rotate and squeeze gently until a uniform triangle shape forms.
  • Repeat steps 3 - 6 with the remaining rice and tuna mixture.
  • Place the rice ball in the middle of the seaweed strip and fold the top corners inward, towards the middle of the rice ball. Use a grain of rice to hold the seaweed together if necessary.
  • Tuck the bottom of the seaweed underneath the seaweed and set aside. Continue with the rest of the rice balls.
  • Garnish the tops of the rice ball with remaining tuna may mixture and serve immediiately.
Keyword rice, rice ball, tuna mayo