→ Main Filling
                    
                      
                        01 - 
                        1 tablespoon olive oil or unsalted butter
                      
                    
                      
                        02 - 
                        1 medium yellow onion, finely diced
                      
                    
                      
                        03 - 
                        1 medium green bell pepper, finely diced (red bell pepper may be substituted)
                      
                    
                      
                        04 - 
                        2 celery ribs, finely diced
                      
                    
                      
                        05 - 
                        3 garlic cloves, minced (or 1 teaspoon garlic powder)
                      
                    
                      
                        06 - 
                        1.1 pounds ground chicken, preferably thigh meat
                      
                    
                      
                        07 - 
                        1 to 1 ½ tablespoons Cajun seasoning, to taste
                      
                    
                      
                        08 - 
                        1 teaspoon smoked paprika
                      
                    
                      
                        09 - 
                        1 tablespoon tomato paste
                      
                    
                      
                        10 - 
                        ½ cup tomato sauce or crushed tomatoes
                      
                    
                      
                        11 - 
                        2 teaspoons light brown sugar or honey
                      
                    
                      
                        12 - 
                        1 teaspoon Dijon or yellow mustard
                      
                    
                      
                        13 - 
                        1 teaspoon Worcestershire sauce (or soy sauce)
                      
                    
                      
                        14 - 
                        ⅓ cup chicken stock or water
                      
                    
                      
                        15 - 
                        Kosher salt and freshly ground black pepper, to taste
                      
                    
                      
                        16 - 
                        Pinch of cayenne pepper (optional for extra heat)
                      
                    
                  
                    → To Serve
                    
                      
                        17 - 
                        6 soft hamburger buns, split and toasted
                      
                    
                      
                        18 - 
                        Sliced dill pickles or sliced jalapeños, for topping (optional)