Preheat oven to 350 degrees. Prep 9x13 baking dish with lining with parchment paper.
Place the carrots, spinach, onion and garlic in food processor and process for 1-2 minutes or until everything is in very small pieces.
Mix all ingredients together in a large mixing bowl.
Scoop out a small handful of mixture (golf-ball sized) and roll into a ball. Place in the prepared baking dish.
Bake in the oven for 35-45 minutes or until meatballs are cooked through.