Preheat your oven to 400°F. Line a baking sheet with parchment paper.
In a large bowl, combine the ground turkey, breadcrumbs, Parmesan cheese, parsley, egg, minced garlic, salt, black pepper, and red pepper flakes (if using). Mix until just combined; do not overmix.
Form the mixture into meatballs, about 1 inch in diameter, and place them on the prepared baking sheet.
Bake the meatballs in the preheated oven for 20-25 minutes, or until they are cooked through and golden brown.
While the meatballs are baking, prepare the honey garlic sauce. In a small saucepan over medium heat, combine the honey, soy sauce, rice vinegar, cornstarch, and water. Stir until the mixture is smooth and bring it to a simmer. Cook for 2-3 minutes until the sauce thickens slightly.
Once the meatballs are done, remove them from the oven and drizzle the honey garlic sauce over them. Toss gently to coat.
Serve immediately, garnished with additional parsley if desired.