Tuna with Horseradish, Lemon and Mustard

This was published in the Washington Post a few weeks ago. I finally got around to whipping this bad boy up ...and it was pretty dang fab. Sweet, sour and spicy - the perfect combination in my book!
From my table to yours...

Tuna with Horseradish, Lemon and Mustard
Ingredients:

• 1 1/2 T prepared horseradish
• 7 ounces plain low-fat Greek-style yogurt
• Fresh ground black pepper
• 1 lemon
• 1 t hot English mustard
• 1 t red wine vinegar
• Leaves from 3 sprigs of flat leave parsley (save some for garnish too)
• 1 1/2 # piece of tuna
• Kosher salt

Directions

• Move the oven rack to 5 inches from the broiler; preheat broiler.
• Line a rimmed baking sheet with foil.
• Combine the horseradish and yogurt. Add pepper to taste.
• Using a grater, zest the lemon (2t) then squeeze the juice (3-4T) into a small bowl. Stir in the mustard and vinegar.
• Add to the lemon-mustard mixture to the horseradish mixture to form a sauce.
• Coarsely chop the parsley to yield 1 1/2 T, then add to the horseradish mixture.
• Taste; the sauce should be hot, sour and salty. Some of the horseradish heat will mellow as the fish cooks.
• Cut the tuna into 4 steaks of equal size. Season lightly with S&P and arrange on baking sheet.
• Use all of the sauce to cover the top of each piece of fish.
• Broil for 5 or 6 min (if you like your tuna on the rare side)
• The sauce should be slightly caramelized on the top.

Serve smoking hot!