Wipe out the skillet and set over medium heat. Melt butter.
Sauté + Toast: Add onion to the butter with a pinch of salt. Cook until softened. Stir in orzo and cook for another minute.
Deglaze: Pour in white wine and add the thyme bundle. Simmer for 2 minutes to cook off the alcohol.
Cook Orzo: Stir in chicken stock. Bring to a simmer, then reduce heat to medium-low. Cook about 6 minutes, stirring often, until most of the liquid is absorbed and orzo is tender.
Finish Creamy Sauce: Add heavy cream, spinach, and parmesan. Stir continuously until spinach wilts and the sauce is thick and creamy. Remove thyme sprigs and season with salt + pepper.
Serve: Spoon orzo into bowls, top with baked chicken meatballs, and garnish with crispy sage, extra parmesan, and fresh parsley or thyme.