Mix together all ingredients for miso glaze and blend well. Place tuna steaks into glaze and flip them around to make sure even coating.
Let marinate for 30 minutes. Meanwhile you should start your horseradish aioli. Add 2 egg yolks, sugar, salt, pepper, and white wine vinegar to food processor. In a seperate bowl mix your 2 oils together. Begin blending the yolk mixture and SLOWLY add a spoonful of oil blend at a time.
Once you can tell the mix is thickening up you can add the remaining oil at once. Let whip for 30 seconds. Remove to bowl and refrigerate until needed. After the tuna has been marinating for 30 minutes, heat your indoor grill or griddle on medium + to high. Place tuna steaks on the grill and leave them in place. Grill them 5 minutes per side for well done, 3 minutes per side for a rare center.
Drizzle some horseradish aioli on a plate, slice the tuna into 1/2" strips and place them on the plate in the aioli sauce.
Drizzle a thin line of aioli over the top of the tuna as well and garnish with thinly sliced watercress. Enjoy!
Just like beef steak, even tuna steak makes for a great entrée. So if you are bothered about piling on unnecessary kilos, then tuna steak is your option. Whether you are hosting an informal lunch or a banquet, you can happily borrow inspiration from Ryan Karcher's miso glazed tuna steak recipe to make your dinner table a win-win one.