In a small bowl, stir together the oats, almond milk, chopped onions, peppers, and garlic. Whisk the eggs and pour them into the oats mixture. Mix in the whole grain mustard, Worcestershire sauce, fresh herbs, and cayenne pepper. Season with salt and pepper, to taste. Let marinate for at least one hour.
Preheat the oven to 375°F. Grease a loaf pan well. Add the ground turkey and spinach to the oat mixture. Season again with salt and pepper, as desired. Mix with a spoon until well combined. Pour the turkey mixture into the loaf pan.
Whisk together the ketchup, balsamic vinegar, and lemon juice. Spread the sauce over the top of the turkey loaf. Cover the pan with foil.
Bake the turkey loaf, covered, for 45 minutes. Remove the foil and continue to cook for an additional 15-20 minutes, or until the internal temperature of the turkey loaf reaches 160°F. Let the meatloaf rest for 15 minutes prior to serving. This will ensure that it continues to cook and doesn't fall apart when removed from the pan. Garnish with additional ketchup and fresh parsley. Enjoy!
Optional: Let rest, covered and refrigerated overnight (or for 8-10 hours). This helps the turkey loaf retain its shape. To reheat: bake at 350°F for 30-40 minutes, or until the internal temperature of the turkey loaf reaches 160°F