It’s been a while since I pulled out some of the tuna fillets we have in the freezer from the incredible fishing trip I took last August. So the other night, I thought it would be a good time to try something different. I started with the basic idea of tuna seared with a wasabi crust and added a new relish of red onions “jellied” in a combination of different vinegars until they are soft, sweet, and tangy all at once.
Gather Up (for the Tuna):
- 4 tuna steaks, about 6 oz each (I started with a 1-1/2 lb fillet and cut into thick steaks)
- 2 tbsp coarse black pepper
- 1 tbsp wasabi powder
- 1 tbsp sesame seeds
- 1 tsp sea salt
- 2~3 tbsp olive oil
Gather Up (for the Onions):
- 1/2 large red onion, sliced thin
- 1 large Anaheim chile, sliced thin across (seeds and stem removed)
- 2 tbsp olive oil
- 1/4 cup water (not shown)
- 2 tbsp red wine vinegar
- 2 tbsp balsamic vinegar
Start with the onions. Heat the olive oil in a saucepan over medium heat. Add the pepper and onion and cook for about 8 minutes until they are starting to soften. Add in the water and vinegars and reduce the heat to a simmer. Continue simmering, stirring every few minutes, for 20 to 30 minutes. In the meantime, get started on the tuna.
Combine the wasabi, pepper, salt, and sesame seeds in a small mixing bowl. Mix them well, then spread about 1/3 of the mixture on a small plate. Press the two largest/flattest faces of each tuna piece into the mixture (adding more to the plate as needed) to coat them well. Set each coated piece on a plate, then sprinkle any leftover mixture onto any bare or lightly coated spots and press in to make it stick.
Let the tuna sit while the onions continue to cook, until they have been reduced to a soft, jelly-like state with a thick sauce around them. As they are getting close, preheat the oven to 400 degrees. And if the onions finish before the tuna is done, keep warm on super-low heat until serving.
Next, preheat a deep, heavy sauté pan on medium-high heat. When the pan is hot, place 2 tbsp olive oil in the pan and place the tuna steak with one wasabi-crusted side in the oil. Sear for 1 minute, then turn over and sear the other side for an additional minute – being careful to keep the wasabi from burning or sticking to the pan.
When both sides of the tuna are seared, transfer to a baking pan and place in the oven for a few minutes longer (depending on how “done” you like your tuna). Shoot for an internal temperature of about 125 degrees for one of the steaks for a nice “medium rare” finish – which was about 4 minutes in the oven after they were seared for my “steaks.”
Serve with some of the jellied onions on top, and some additional on the side. This one goes well with yesterday’s Orange Hazelnut Salad too. Dig in!
Purely Primal 
I’ve never cooked tuna before, and honestly, I’ve been intimidated by how it’s somewhat “raw” inside. If I were to cook it longer would it be dry? Would I ruin it? Also, was the 400 degrees convection, or regular oven? Thanks!
~Sharon
A lot of people are uncomfortable with fish that is a little “raw” inside – though good tuna is best when cooked like a good steak and you leave it rare in the middle. That said, if you are careful about it you can cook it to be more done without completely ruining it. Shoot for maybe 6 minutes (8 at the most) in the oven after searing, or about 145 degrees internal temperature with the thermapen. It will dry out a little, but the searing helps hold in the moisture. More than anything, cooking tuna all the way firms up the texture and makes it a bit tougher – again, a lot like a steak.
For the oven time – I had ours set on ‘regular’ bake when cooking them. Good luck!