Marinated Halibut on Radish Sprout and Fennel Salad

Preparation

1. Prepare fish:

   Step 1

   Simmer raisins in vinegar in a small saucepan until raisins are plump, 3 to 5 minutes, then cool.

   Step 2

   Cook onion in 1 tablespoon oil in a 12-inch nonstick skillet over moderate heat, stirring occasionally, until softened, 4 to 6 minutes. Remove skillet from heat and transfer half of onion to a 9-inch square glass or ceramic baking dish with a slotted spoon, spreading evenly. Reserve remaining onion.

   Step 3

   Cut fish into 6 equal pieces. Pat dry and season with salt and pepper. Spread potato starch on a plate and dredge fish in it, shaking off excess.

   Step 4

   Heat remaining 1 1/2 tablespoons oil in skillet over moderately high heat until hot but not smoking, then sauté fish, skin sides down, until lightly browned, 1 1/2 to 3 minutes. Turn fish over and sauté until lightly browned and just cooked through, 1 1/2 to 3 minutes more.

   Step 5

   Arrange fish on top of onion in baking dish, then top with reserved onion and drizzle with raisins and vinegar. Cool completely, then marinate, covered and chilled, at least 8 hours. Bring to room temperature.

2. Make salad:

   Step 6

   Tear enough fennel fronds to measure 1 tablespoon. Trim stalks flush with bulb and discard stalks. Quarter bulb lengthwise, then cut lengthwise into paper-thin slices with a mandoline or other manual slicer. Transfer slices to a bowl and toss with radish sprouts.

   Step 7

   Whisk together vinegar and oil, then whisk in sugar and salt and pepper to taste. Toss vegetables with half of dressing and divide among 6 plates.

3. Step 8

   Remove onion from top of fish, reserving it, and put a piece of fish on top of each salad. Mound all of onion and raisins on top of fish, then drizzle with remaining dressing and sprinkle with fennel fronds.