Serves6
                    
                
                
                    
                        
                            - Active time:45 min
- Start to finish:9 hr
 
            
            
                
                
                
    
      
          
          
          
              
              
              
          
          
          
          
          
              
              
              April 2001
            
          
          
      
  
                
                
            
            
            
                The agrodolce (tart-and-sweet) flavors of vinegar and raisins used in marinating the fish are typical of Jewish-Italian cooking.
            
            
            
            
            
                
                    
                    
                    
                        
                            For fish
                            
                            
                                
                                    
                                        - 
                                            2
                                            tablespoons
                                            golden raisins
                                            
                                        
- 
                                            1/2
                                            cup
                                            white balsamic vinegar, or 1/2 cup cider vinegar mixed with 2 tablespoons sugar
                                            
                                        
- 
                                            1
                                            
                                            medium red onion, thinly sliced crosswise
                                            
                                        
- 
                                            2 1/2
                                            tablespoons
                                            olive oil
                                            
                                        
- 
                                            1
                                            
                                            (1-lb) piece halibut fillet with skin (about 1 1/2 inches thick) or 2 (8-oz) red snapper fillets with skin
                                            
                                        
- 
                                            2
                                            tablespoons
                                            potato starch
                                            
                                        
 
                    
                        
                            For salad 
                            
                            
                                
                                    
                                        - 
                                            1
                                            
                                            large fennel bulb (sometimes called anise) with fronds 
                                            
                                        
- 
                                            2 1/2 
                                            
                                            oz radish sprouts or watercress sprigs, trimmed (2 cups) 
                                            
                                        
- 
                                            2 
                                            tablespoons
                                            white balsamic vinegar, or 2 tablespoons cider vinegar mixed with 1 1/2 teaspoons sugar
                                            
                                        
- 
                                            1/4 
                                            cup
                                            olive oil
                                            
                                        
- 
                                            1/4 
                                            teaspoon
                                            sugar
                                            
                                        
 
                    
                 
            
            
            
            
            
            
            
            
                
                    
                    
                    
                        
                            
                                Prepare fish
                                
                                
                                    
                                        - 
                                            
                                            Simmer raisins in vinegar in a small saucepan until raisins are plump, 3 to 5 minutes, then cool. 
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                                            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. 
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                                            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.  
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                                            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. 
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                                            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. 
 
                        
                            
                                Make salad:
                                
                                
                                    
                                        - 
                                            
                                            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. 
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                                            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. 
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                                            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. 
 
                        
                    
                    Cooks' note: Fish can be marinated up to 2 days.