Prepare the breadcrumb mixture: In a small bowl, combine the breadcrumbs and milk. Let this sit for 3-4 minutes until the breadcrumbs have absorbed the liquid and formed a soft, porridge-like paste. You'll feel the mixture turn from dry crumbs to a cohesive, squishy texture when pressed between your fingers.

Mix the meatball base: In a large mixing bowl, combine the minced beef, grated onion, crushed garlic, soaked breadcrumbs, beaten egg, parsley, oregano, black pepper, salt, and Parmesan. Use your hands to gently mix everything together — the mixture should feel cool and slightly tacky. Stop mixing the moment you no longer see streaks of egg; overworking makes the meatballs dense and tough.

Shape the meatballs: Lightly wet your palms with cold water to prevent sticking. Roll the mixture into 20-24 even balls, each about the size of a golf ball — roughly 35g each. Place them on a tray lined with baking paper as you go. The surface of each ball should feel smooth and slightly damp, with no visible cracks.

Sear the meatballs: Heat the olive oil in a large frying pan over medium-high heat until it shimmers and a test piece of meat sizzles immediately on contact — that's around 190°C. Carefully place half the meatballs in the pan, leaving a finger's width between each. Cook without moving them for 4-5 minutes, until the bottoms turn a deep mahogany brown and a crust forms. You'll hear a steady sizzle; if it's spitting aggressively, the heat is too high. Turn the meatballs using tongs and sear the other side for another 3-4 minutes. The surface should look caramelised, not burnt, and the kitchen will smell rich and savoury. Transfer to a plate and repeat with the remaining meatballs.

Build the sauce: Reduce the heat to medium. Add the tomato purée to the pan and stir constantly for 1 minute — it will darken from bright red to a deep russet colour and release a concentrated, sweet aroma. Pour in the chopped tomatoes and beef stock, scraping the bottom of the pan with a wooden spoon to lift the browned bits. The liquid will bubble and thicken slightly, turning a glossy brick-red colour after 2-3 minutes.

Finish cooking the meatballs: Return all the seared meatballs to the pan, nestling them into the sauce. Reduce the heat to low, cover the pan, and let them simmer gently for 10-12 minutes. The sauce should barely bubble — just an occasional lazy burp. When ready, the meatballs will feel firm but give slightly when pressed, and a skewer inserted into the centre should come out hot to the touch. The sauce will have thickened to coat the back of a spoon.

Rest and garnish: Turn off the heat and let the pan sit uncovered for 5 minutes. This rest allows the juices to redistribute through the meat. Just before serving, tear fresh basil leaves over the top — the heat from the sauce will release their fragrance immediately.