This recipe features extra-large, tender beef meatballs slowly cooked in a rich and full-bodied red wine gravy, perfect for serving over creamy Gruyère mashed potatoes with baby spinach. The meatballs are first baked, then sautéed to develop a golden crust before being simmered in a thickened red wine and tomato sauce. The accompanying mashed potatoes are infused with butter, warm whole milk, and melted Gruyère cheese, with fresh baby spinach wilted into the mixture for a creamy, flavorful side dish that complements the robust meatballs.