Preheat your oven to 400°F.
Pour the stuffing mix into a small bowl. Add the cup of hot water and stir until well combined. Set it aside to soak up the water while you prepare the rest of the ingredients.
Peel and chop the carrots into large chunks. Place them in a food processor and pulse until finely diced. Measure out ⅔ cup and set aside in a large mixing bowl. Discard any leftovers.
Chop the celery into large chunks. Place them in a food processor and pulse until finely diced. Measure out ⅔ cup and set aside in the mixing bowl with the carrots. Discard any leftovers
Chop the onion into large chunks. Separate the parsley and rosemary leaves from the stems. Keep the leaves and discard the stems. Place the onion, garlic, sage, rosemary, and parsley in the food processor and pulse until finely diced.
Melt the 2 tablespoons of butter in a large skillet over medium heat. Once hot, add the diced carrots, celery, onion mixture, salt, and pepper. Cook for about 5 minutes or until soft and fragrant.
Stir in the rehydrated stuffing mix. Use a spatula to break up the stuffing mix and thoroughly incorporate it into the cooked vegetable mixture. Once incorporated, remove it from the heat and pour the stuffing mixture into a large mixing bowl.
Add the ground turkey and use your hands or a large mixing spoon to combine the turkey and stuffing mixture. Make sure the turkey and stuffing are well combined, but be careful you don't overmix.
Use a small cookie scoop to form the turkey mixture into 40-45 small meatballs. The meatballs will be about the size of a golf ball. Place the formed meatballs on a large baking sheet.
Bake the Thanksgiving meatballs for 20-25 minutes, or until the internal temperature reaches at least 165°F.
While the meatballs are cooking, prepare the homemade gravy. Melt the 4 tablespoons of butter in a small saucepan over medium-low heat.
Once melted, stir in the flour. Whisk until smooth and cook for about 30 seconds.
Add the chicken broth and whisk continuously until slightly thickened. If your chicken broth is warm, the gravy will thicken quickly. If it's cold from the fridge, it may take 5 minutes or more to thicken. Add salt and pepper to taste.
Serve the Thanksgiving meatballs drizzled with warm gravy, and enjoy!