Don't be intimidated by the amount of wasabi in this recipe; it is cooked which mellows out the flavour. This is as good as anything you will get in a restaurant.
This simple-to-make recipe is guaranteed to bring you compliments- I would give it many more stars if I could. This creamy sauce is worth every bit of exercise you might feel compelled to do-- count your calories elsewhere, and just enjoy this dish! Your tastebuds will thank you! My recommendations: 1) You must use a full-bodied, dry white wine, as the sauce's end result relies on that. I recommend Mersault. 2) You should dedicate 20 minutes to making the sauce. The white wine, vinegar, shallot mixture should take at least that long to reduce, as it should gently boil over medium-high heat. Don't let it boil rapidly, but don't let it just simmer either. 3) Use about half the butter called for, or use all of the butter and let the sauce reduce. Experience has taught me that this sauce is always better when it is thicker and richer. If the recommended amount of butter is used, the result is a thin, mild sauce. By reducing the butter, you'll create a denser, creamier sauce that seems more appropriate for a thick tuna steak. 4) If you take my recommendation for cutting back on the butter, realize that this will reduce the amount of sauce you make to about 3-4 adult portions. 5) Lastly, I recommend serving this with orzo, freshly sliced tomatoes, and deep fried spinach (found on allrecipes.com). The colors, textures, and flavors blend very well. - 21 Apr 2004 (Review from Allrecipes USA and Canada)
I liked this recipe so much that I created an account on the site just to write this . I cut an 8oz tuna steak lengthwise for a 4oz serving for my wife and I. After coating each in olive oil and salt/pepper, I seared it on the stove, watching the middle of each half to where I had just the perfect sear:raw ratio. For presentation, I cut each fillet into several thin (about 1/8 inch thick) medallions on the plate, and fanned them out. For the sauce, I haven't been happy with the wine, so I substituted apple juice in for it instead. I still put the white wine vinegar in it, however. Apple juice instead of wine might not sound that great, but when you reduce it down far enough with the vinegar and onions, you get a delious, syrupy base. I only used 1 stick of butter, and I think it was perfect that way. I stuck with the recipe on the 1tbs of soy and wasabi, and was very happy with the result. Even though the "heat" pretty much cooks out, the beauty in this recipe is the taste combination. Be very careful while the butter emulsifies. You want a good thick sauce, but it REALLY wants to boil on you. Watch the heat. This is where cooking with gas helps, because you have that instant temperature control. Once the sauce was done, I drizzled it over the tuna medallions, and served it with rice. Fantastic. - 07 Dec 2007 (Review from Allrecipes USA and Canada)
What you want here is the sauce, as it's more delectably remarkable and delicious beyond any I have EVER encountered!! Use yellowfin or ahi/sushi grade tuna, thickly sliced. If you don't marinate it, at least cover it with olive oil then coat generously with black/white sesame seeds which have been combined with chopped fresh herbs such as Italian parsley, cilantro, basil, etc., whatever you may have on hand. Place the fish on wax paper and refrigerate for 30 minutes. Heat olive oil in a heavy skillet, and quickly sear the tuna on both sides (1.5 minutes), do not let the tuna cook or you destroy the true flavor (it's like eating the finest rare beef steak, you can't tell the difference). Served with the butter and wild rice/lemon pilaf or greens, it's total heaven! And all I do with the refrigerated leftover sauce and to cook another tuna meal is let the butter get to room temperature, scoop an amount on a plate, and set the hot fish upon it. Unless you reheat the butter VERY carefully and slowly, it will separate such as in a clarification process, changing its flavor and quality. This is absolutely my favorite meal!!!! TEN stars on the sauce, and wasabi away to your tasting! - 21 Jul 2007 (Review from Allrecipes USA and Canada)