In a large bowl, combine ground beef, ground pork substitute, breadcrumbs, chopped green onions, minced garlic, grated ginger, soy sauce, sesame oil, honey, salt, black pepper, and red pepper flakes (if using).
Mix all ingredients together until well combined. You can use your hands for mixing but be sure to not over-mix.
Form the mixture into small meatballs (about 1 inch in diameter) and place them on a baking sheet.
Heat a skillet over medium heat. Brown the meatballs in batches for about 2-3 minutes on each side until they have a golden color (this step is optional but adds flavor).
Transfer the browned meatballs into the crockpot. Pour the teriyaki sauce over the top of the meatballs, ensuring they are well coated.
Cover the crockpot and cook on low for 4-6 hours or on high for 2-3 hours, until the meatballs are cooked through and tender.
Once done, carefully remove the meatballs from the crockpot using a slotted spoon.
Serve the meatballs on a platter, garnished with sesame seeds and extra chopped green onions for added flavor and presentation.
Notes
Serve with steamed jasmine rice or sautéed vegetables. Drizzle extra teriyaki sauce on top for added flavor.