01 - In a large mixing bowl, combine the ground beef, breadcrumbs, Parmesan cheese, egg, minced garlic, milk, salt, pepper, and chopped basil. Gently fold everything together until just evenly combined—avoid overworking the meat or the meatballs will become tough.
02 - Roll the mixture into golf ball–sized portions, yielding approximately 16 meatballs. Place them on a plate or sheet pan as you work.
03 - Heat the olive oil in a large skillet over medium heat. Add the meatballs in a single layer and cook, turning frequently, until golden brown on all sides, about 6 minutes. Transfer to a plate and set aside—they will finish cooking in the sauce.
04 - In the same skillet, add the chopped onion and sauté until softened and translucent, 3 to 4 minutes. Add the minced garlic and cook for 30 seconds until fragrant.
05 - Pour in the crushed tomatoes and broth. Season with salt, pepper, and sugar if using. Stir well and let the sauce simmer for 5 minutes to allow the flavors to meld.
06 - Stir in the heavy cream and 1/4 cup Parmesan cheese until smoothly incorporated. Fold in the chopped basil, then return the browned meatballs to the skillet, nestling them into the sauce.
07 - Reduce heat to low and simmer uncovered for 15 to 20 minutes, gently turning the meatballs occasionally, until they are cooked through and the sauce has thickened to a creamy consistency.
08 - Taste the sauce and adjust seasoning as needed. Garnish with fresh basil leaves and serve over cooked pasta, rice, or alongside crusty bread.