Tip the breadcrumbs into a mixing bowl and pour over the milk. Stir then set aside for 5 mins until the bread has absorbed the milk. Mix in the pork, harissa, lemon, parmesan, anchovies and parsley, season with a good few cracks of black pepper and 1/2 tsp fine sea salt. Form into 60 meatballs, around 25g each. Transfer to a baking tray. If not using right away, cover and set aside in the fridge until needed. Uncooked meatballs will keep covered and chilled for up to two days.

Heat the oil in a large ovenproof casserole dish or pan over a medium-high heat, add the onions and basil stems with a pinch of salt. Cook for 10 mins until beginning to soften, then mix in the garlic. Cook for a further 2 mins. Stir in the tomato purée, sugar and vinegar. Cook for 3-4 mins, stirring regularly, until caramelised. Tip in the tomatoes, breaking them up with the spoon. Bring to a gentle simmer, then mix in the basil leaves and butter. Cook for 20 mins, until reduced and thickened, season to taste. Will keep chilled for up to three days. Leave to cool first.

Heat the oven to 180C/160C fan/gas 4. Transfer the tomato sauce to a baking dish, if needed, and dot the meatballs evenly over the top. Drizzle a little olive oil over, cover with foil and bake for 25 mins. Remove the foil and bake for a further 25 mins, until the meatballs are cooked through and browned. Will keep chilled for up to four days.