Combine the minced short rib, grated pear, grated onion, garlic, soy sauce, sugar, sesame oil, pepper, pine nuts, and starch in a bowl.
Mix by hand, folding rather than squeezing, just until everything is evenly distributed — about 1 minute. Overworking it toughens the meat.
Divide into 8 portions and shape into oval patties about 1.5 cm / just over half an inch thick, pressing a slight dimple into the center of each so they cook flat instead of doming.
Cover and refrigerate for 20 to 30 minutes. This firms the fat and holds the patties together on the grill.
Heat a grill pan, cast iron pan, or charcoal grill to medium-high and brush lightly with oil.
Cook the patties for 3 to 4 minutes per side, until a deep brown crust forms and the center reaches 71°C / 160°F on a meat thermometer.
Rest for 2 minutes, then scatter with scallions and sesame seeds before serving.