1
                    
                        
                                    - 
                                        
                                            ¾
                                                cup
                                         onion, yellow (minced) 
- 
                                        
                                            3
                                                tbsp
                                         butter, unsalted 
 
                    Cook the onion slowly in butter until transparent, but not browned. Set aside in a mixing bowl.
                 
                
                    2
                    
                        
                                    - 
                                        
                                            1½
                                                lb
                                         ground beef, 10% fat 
- 
                                        
                                            1½
                                                tsp
                                         salt 
- 
                                        
                                            ⅛
                                                tsp
                                         pepper, black 
- 
                                        
                                            ⅛
                                                tsp
                                         thyme 
- 
                                        
                                            1
                                         egg 
 
                    Add the beef, butter, salt, pepper, thyme, and the egg to the mixing bowl and combine by hand until a smooth paste has formed.
                 
                
                    3
                    
                    Form 6oz patties about 3/4" thick.  Set aside on parchment paper.
                 
                
                    4
                    
                    Spread the flour in a shallow dish, and dredge each patty until coated.  Shake off any excess and place them back on the paper.
                 
                
                    5
                    
                    Heat the oil in a skillet large enough to accomodate all the hamburgers in a single layer. Once the oil is shimmering hot, place the patties down in a single layer. DO NOT touch them until they have browned half-way up the sides (about 2–3 min).
                 
                
                    6
                    
                    Very gently, turn the patties over and continue to sauté them until browned fully up the sides (another 2–3 min).  DO NOT touch them at all while they cook, and handle them as little as possible while turning.
                 
                
                    7
                    
                        
                                    - 
                                        
                                            ½
                                                cup
                                         vermouth 
- 
                                        
                                            2
                                                tbsp
                                         butter, unsalted 
 
                    Gently transfer the patties to a platter and leave in a warm place.  Discard the fat in the skillet, and add the vermouth.  Reduce it until it coats the back of a spoon, and then melt in the final portion of butter.  Reduce just a bit further, and the pour the sauce over the patties and serve.