Seared Tuna With Caviar

2 pounds center-cut yellow or blue fin tuna, 3 inches in diameter
1 egg white, beaten until foamy
½ cup fresh coarsely ground white pepper
½ teaspoon ground coriander seed
3 to 4 tablespoons grape-seed or safflower oil
8 cups mixed greens: combination of bibb, mache, radicchio and chicory, dressed with vinaigrette
Sauce (see recipe)

Eight servings

Brush egg white on all sides of the tuna with a pastry brush.
Mix the ground pepper and coriander and press the tuna into this mixture, using as much of it as necessary to cover each side and the ends.
Heat a heavy saute pan and pour about half of the oil into the pan. Bring to the smoking point and carefully place the tuna in the pan. Sear each side until dark brown and crusty, adding more oil if needed to keep the tuna from sticking. Sear the ends as well. Each side should take about one to one and a half minutes. Remove the tuna and let it rest for at least 10 minutes before slicing.
Using a very sharp knife, cut the tuna into one-half- to one-third-inch slices, allowing three slices per serving.
Arrange the dressed salad greens on each of eight plates at 12 o’clock.
In a semicircle, overlap three slices of tuna below the greens, with the top edges of tuna resting on the salad. At the base of each piece of tuna, place a dollop of the sauce.

30 minutes