01 - In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, egg, minced garlic, milk, salt, black pepper, and chopped basil. Gently mix until just combined — avoid overworking the meat.
02 - Roll the mixture into golf ball–sized meatballs, yielding approximately 16 portions. Place on a tray and set aside.
03 - Heat olive oil in a large skillet over medium heat. Add the meatballs and cook, turning frequently, until evenly browned on all sides, about 6 minutes. Remove from the skillet and set aside — they will finish cooking in the sauce.
04 - In the same skillet, add the chopped onion and sauté until softened, 3 to 4 minutes. Add the minced garlic and cook for an additional 30 seconds until fragrant.
05 - Pour in the crushed tomatoes and broth. Season with salt, pepper, and sugar if using. Stir to combine and let the sauce simmer for 5 minutes.
06 - Stir the heavy cream and Parmesan cheese into the sauce. Fold in the chopped basil until evenly distributed.
07 - Return the browned meatballs to the skillet, nestling them into the sauce. Simmer uncovered on low heat for 15 to 20 minutes, gently turning the meatballs occasionally, until cooked through and the sauce has thickened.
08 - Taste the sauce and adjust seasoning as needed. Garnish with fresh basil leaves and serve over pasta, rice, or alongside crusty bread.