Slice 
                                            beef sirloin
                                             across the grain into strips Zest 
                                            lemon
                                             and 
                                            orange
                                             In blender add 
                                            onions
                                            , lemon zest, orange zest, 
                                            salt
                                            , 
                                            black pepper
                                            , 
                                            sumac
                                            , 
                                            berbere
                                            , and 
                                            white vinegar
                                            . Add mixture to meat in the pot that you will be cooking the meat in. Add 
                                            tomato
                                             and 
                                            green chili
                                            . Marinate for 
                                            2 hours
                                             to 
                                            3 hours
                                            . Cover pot and turn heat to high. Bring to boil, turn heat to medium low and cover Meat should be tender and shold have no liquid Add 
                                            butter
                                             or 
                                            rendered beef fat
                                            . Continue cooking for 
                                            10 minutes
                                             Slice 
                                            red onion
                                            , add 
                                            sumac
                                            , and 
                                            salt
                                            . Let sit for at least 
                                            15 minutes
                                            . Add juice from 
                                            lemon
                                            . Chop 
                                            flat leaf parsely
                                            . Add parsely, onions, and 
                                            tahini sauce
                                             to beef mixture.