Line a large baking sheet with foil and preheat oven to 425 degrees F.
Use hands to mix all meatball ingredients together until combined. Roll tablespoon sized balls and place on lined baking sheet. Bake in preheated oven for 13-18 minutes until browned.
Make the sauce while the meatballs are cooking. Combine soy sauce, 1/4 cup of water, dry sherry, brown sugar, garlic and ginger in a saucepan over medium heat until the sugar has dissolved, just for a few minutes. Turn the sauce into a glaze by separately mixing the cornstarch with the tablespoon of water and then adding it to the soy sauce mixture. Simmer on low until thickened.
Add the cooked meatballs to the sauce and toss to coat.
Top with green onions and sesame seeds before serving.