If you're looking for something elegant to serve to guests, sometimes the answer is counterintuitive: don't cook. Cut.
You see steak tartare in a lot of restaurants, and it's definitely possible to make at home, but tuna tartare is a little less daunting, and when I found this tuna-beet tartare recipe in Michel Richard's Happy In the Kitchen, I knew it'd be perfect for two things: a) blogging about, and b) serving.
So really all you do for this tartare is cut cubes of beet, tuna, and jicama, and then toss them in a dressing of soy sauce, lemon juice, and olive oil. That's it. Oh, you do roast the beets first. And add some chives at the end. Chefs do love their chives.