Preheat your oven to 375°F (190°C) if baking. Line a baking sheet with parchment paper for easy cleanup.
In a large mixing bowl, combine the ground chicken or turkey, breadcrumbs, grated carrot, spinach, grated cheese (if using), garlic powder, onion powder, egg, and a pinch of salt and pepper. Mix everything together until well combined.
Using your hands or a spoon, form the mixture into small, toddler-friendly meatballs (about 1-inch in diameter).
If baking, place the meatballs on the prepared baking sheet and bake for 15-20 minutes or until golden brown and cooked through.
If frying, heat olive oil in a frying pan over medium heat. Cook the meatballs in batches, turning them until they are golden and cooked through, about 5-7 minutes per batch.
Let the meatballs cool slightly before serving to your toddler.