In a large mixing bowl, combine the ground beef, breadcrumbs, egg, chopped sun-dried tomatoes, and spinach. Add Italian seasoning and mix thoroughly until incorporated.

Scoop out portions of the meat mixture and roll them into balls about 1.5 inches in diameter, placing on a parchment-lined tray.

Spray the bottom of the slow cooker with cooking spray or olive oil. Place meatballs snugly into the slow cooker.

In a separate bowl, whisk together broth and heavy cream until smooth. Pour over the meatballs.

Cover and cook on low for 6-8 hours or high for 3-4 hours until meatballs reach an internal temperature of 165°F.

Ladle meatballs and sauce onto plates and garnish with parsley or Parmesan cheese before serving.