Serves6 (main course)
                    
                
                
                    
                        
                            - Active time:45 min
 
                        
                            - Start to finish:45 min
 
                        
                    
                
             
            
            
                
                
                
    
      
          
          
          
              
              
              
          
          
          
          
          
              
              
              July 2008
            
          
          
      
  
                
                
            
            
            
                Once a way to make use of stale tortillas (by toasting and/or frying them), tostadas are so good that it wasn’t long before people simply started using fresh tortillas. After biting into these layers of flavor—crunchy, creamy, luscious—you’ll see why.
            
            
            
            
            
                
                    
                    
                    
                        
                            
                            
                            
                                
                                    
                                        - 
                                            1
                                            
                                            medium white onion
                                            
                                        
 
                                    
                                        - 
                                            1
                                            
                                            tomatoes, quartered
                                            
                                        
 
                                    
                                        - 
                                            2
                                            
                                            large garlic cloves
                                            
                                        
 
                                    
                                        - 
                                            1 or 2
                                            
                                            fresh serrano chiles, stemmed
                                            
                                        
 
                                    
                                        - 
                                            1/2 cup plus 2
                                            tablespoons
                                            vegetable oil, divided
                                            
                                        
 
                                    
                                        - 
                                            3
                                            cups
                                            shredded iceberg lettuce
                                            
                                        
 
                                    
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                                            6
                                            
                                            large radishes, halved and sliced
                                            
                                        
 
                                    
                                        - 
                                            1/2 
                                            cup
                                            chopped cilantro, divided
                                            
                                        
 
                                    
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                                            1
                                            
                                            rotisserie chicken, meat coarsely shredded (4 cups)
                                            
                                        
 
                                    
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                                            6
                                            
                                            (6-inch) corn tortillas
                                            
                                        
 
                                    
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                                            1
                                            
                                            (1-lb) can refried beans, heated
                                            
                                        
 
                                    
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                                            1
                                            
                                            avocado, halved, pitted, and peeled
                                            
                                        
 
                                    
                                        - 
                                            1/2
                                            cup
                                            Mexican crema or sour cream
                                            
                                        
 
                                    
                                        - 
                                            1/4
                                            cup
                                            crumbled queso añejo (aged white cheese, also called cotija) or ricotta salata
                                            
                                        
 
                                    
                                
                            
                         
                    
                 
            
            
            
            
            
                
            
            
            
            
                
                    
                    
                    
                        
                            
                                
                                
                                
                                    
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Preheat broiler.
                                         
                                    
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Cut half of onion into 3/4-inch wedges, then chop remainder. Toss onion wedges, tomatoes, garlic, and whole chiles with 2 Tbsp oil in a 4-sided sheet pan, spreading in 1 layer.
                                         
                                    
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Broil about 4 inches from heat until softened and charred, 10 to 15 minutes.
                                         
                                    
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Meanwhile, toss together lettuce, radishes, chopped onion, and half of cilantro.
                                         
                                    
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Purée tomato mixture in a blender along with one or both roasted serranos (to taste) and 1 tsp salt until smooth (use caution when blending hot foods). Transfer purée to a bowl and stir in chicken, remaining cilantro, and salt to taste.
                                         
                                    
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Heat remaining 1/2 cup oil in a heavy medium skillet over medium-high heat until it shimmers. Fry tortillas, 1 at a time, turning once or twice and pressing with tongs to immerse, until golden brown, 45 to 60 seconds per tortilla. Drain briefly on paper towels, then transfer to plates.
                                         
                                    
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Spread tortillas thickly with heated refried beans, then top with chicken mixture. Slice avocado over tostadas and dollop with crema.
                                         
                                    
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Mound lettuce mixture on top and sprinkle with cheese.