Preheat the oven to 375°F and line a baking sheet with parchment paper.
In a large bowl, combine the ground beef, 1/3 cup of the scallions, ginger, garlic, egg, panko breadcrumbs, soy sauce, and sesame oil.
Mix with your hands until the ingredients are evenly distributed but do not overwork the meat.
Divide the mixture into 8 equal portions and shape each into a small loaf. Place the loaves on the prepared baking sheet.
Stir the ketchup until smooth, then brush it evenly over the top and sides of each mini meatloaf.
Bake for 25 minutes, or until the internal temperature reaches 160°F.
Remove from the oven and let the meatloafs rest for 5 minutes before serving. Sprinkle the remaining scallions over the top.