Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper for easy cleanup.
In a large bowl, combine the ground turkey (or beef), breadcrumbs, chopped onion, minced garlic, parsley, egg, salt, and pepper. Mix until all ingredients are well incorporated.
Use your hands to shape the mixture into small meatballs, about 1 inch in diameter. Place them on the prepared baking sheet.
Bake the meatballs in the preheated oven for about 15-20 minutes, or until they are cooked through and golden brown.
While the meatballs are baking, whisk together the cranberry sauce, soy sauce, Dijon mustard, and red pepper flakes in a medium saucepan over medium heat. Let it simmer for about 5 minutes, stirring occasionally.
Once the meatballs are done, remove them from the oven. Pour the cranberry glaze over the meatballs and gently toss to coat them evenly.
Return the meatballs to the oven for an additional 5 minutes, allowing the glaze to set.
Remove from the oven and let cool for a few minutes before serving.