01 - In a large bowl, combine ground beef, breadcrumbs, Parmesan cheese, egg, minced garlic, milk, salt, black pepper, and chopped basil. Mix gently until just combined — avoid overmixing to keep the meatballs tender.
02 - Roll the mixture into golf ball–sized meatballs, yielding approximately 16 pieces. Place them on a plate or tray as you work.
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 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 the crushed tomatoes and broth into the skillet. Stir in salt, pepper, and sugar if using. Bring to a simmer and cook for 5 minutes to allow the flavors to meld.
06 - Stir the heavy cream and 1/4 cup Parmesan cheese into the sauce. Fold in the chopped fresh basil until evenly distributed.
07 - Return the browned meatballs to the skillet, nestling them into the sauce. Simmer uncovered over 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 cooked pasta, rice, or alongside crusty bread.