In a bowl, combine all the ingredients for the meatballs and use your hands to mix. If the meatballs seem too wet, add a bit more panko.
Form into tablespoon-sized meatballs.
Fry the Chicken Meatballs:
Heat the cooking oil in a wide pot over medium heat. Add the meatballs in an even layer and cook for 3-4 minutes per side until browned all over, about 12 minutes total. Transfer to a plate. It is okay if the meatballs are not cooked through as they will cook in the broth later.
Cook the Aromatics:
Heat the sesame oil in the same pot over medium heat. Add the onion and cook for 3-4 minutes. Add the sliced shiitake caps and cook for 7-8 minutes until well-browned all over.
Add the garlic and ginger and cook for 1 minute or until fragrant.
Prepare the Soup Broth:
Add the green curry paste to the aromatics and lightly mash it into the aromatics. Cook for 45 seconds until fragrant.
Pour in the chicken stock and bring to a boil. Taste and season with salt and pepper.
Cook the Meatballs:
Add the meatballs to the broth and reduce heat to low. Simmer for 15 minutes or until the meatballs are cooked through.
Finish the Curry:
Bring the broth to a low boil and addd the coconut milk and the tomatoes. Cook for 5-7 minutes more. Turn off the heat.
To Serve:
Ladle the broth and meatballs over cooked noodles, rice, or vegetables. Garnish with cilantro and the reserved scallions. Enjoy!