Makes 6 (6- by 1 1/2-inch strips, with leftovers) or 36 (1 1/2-inch) brownie squares
                    
                
                
                    
                        
                            - Active time: 30 min
 Total time: 1 3/4 hr 
                        
                    
                
             
            
                
                    
                    This brownie is outstanding. It’s moist all the way to the edges, with a deep, dark, rich chocolaty essence. 
                
            
            
                
                
                
    
      
  
                
                
            
            
            
            
            
            
            
                
                    
                    
                    
                        
                            
INGREDIENTS:
                            
                            
                        
                    
                        
                            
                            
                            
                                
                                    
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                                            8 ounces bittersweet (60% cacao) chocolate, chopped
                                            
                                        
 
                                    
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                                            1 stick (1/2 cup) plus 3 tablespoons unsalted butter plus more for pans
                                            
                                        
 
                                    
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                                            1 cup packed light brown sugar
                                            
                                        
 
                                    
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                                            3 large eggs
                                            
                                        
 
                                    
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                                            1 teaspoon pure vanilla extract
                                            
                                        
 
                                    
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                                            1/4 teaspoon salt
                                            
                                        
 
                                    
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                                            2/3 cup all-purpose flour
                                            
                                        
 
                                    
                                
                            
                         
                    
                 
            
            
            
            
            
            
            
            
                
                    
                    
                    
                        
                            
                        
                            
                        
                            
                                
                                
                                
                                    
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Heat oven to 325°F with rack in middle.
                                         
                                    
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Butter pan, then line bottom and 2 opposite sides with a long sheet of parchment paper allowing a 2-inch overhang on the 2 sides and trimming paper to fit. Butter parchment (not overhang).
                                         
                                    
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Melt chocolate and butter in a metal bowl set over barely simmering water, stirring occasionally until smooth. Cool to lukewarm.
                                         
                                    
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Whisk in brown sugar until blended. Whisk in eggs, one at a time, whisking after each addition until well blended. Stir in vanilla, salt, and flour until smooth.
                                         
                                    
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Spoon batter into prepared pan, smoothing top, and bake until set and a wooden toothpick inserted in center comes out clean, 25 to 30 minutes. Transfer brownies in pan to a wire rack; let cool for 20 minutes. Holding onto parchment paper overhang, lift brownies from pan and let cool completely on rack. Cut into serving pieces.
                                         
                                    
                                
                             
                        
                            
                                COOKS’ NOTES:
                                
                                
                                    
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Brownies improve in flavor and slice best when made 1 day ahead. When completely cooled, return, still on parchment, to pan and keep at room temperature, well wrapped in plastic or foil. 
                                         
                                    
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Leftovers keep 5 days (but the brownies are so good, you’ll be lucky if there are any left at the end of 5 days!).