Gently heat the milk in a small saucepan until steaming, then remove from the heat and leave to cool slightly. Combine the flour, salt, yeast and caster sugar in a large bowl. Make a well in the centre, and pour in 4 tbsp olive oil and 250ml of the warm milk. Stir to combine, adding the rest of the milk if the dough feels dry. Tip out onto a lightly floured surface and knead for 10 mins, then put in a lightly oiled bowl. Cover and leave to rise for 1 hr 30 mins-2 hrs until doubled in size.

To make the sauce, heat the oil in a saucepan over a low heat and fry the onion with a large pinch of salt for 12-15 mins, or until the onion is softened and translucent. Add the garlic and fry for 1 min more. Stir in the tomatoes, tomato purée, oregano and sugar. Bring to the boil, then reduce to a simmer and cook uncovered for 15-20 mins, or until the sauce has thickened. Season. If you prefer a smooth sauce, blitz with a hand blender.

Lightly oil a roughly 33 x 23cm baking tray. Roll the risen dough out slightly with a rolling pin, then stretch it over the tray and into the corners, pushing it up the edges to make a lipped crust. Spread over the tomato sauce and top with most of the mozzarella. Cover and leave to rest for 30 mins.

Heat the oven to 240C/220C fan/gas 8 with a baking sheet inside to heat up – it should be large enough to hold the pizza tray. Combine the pork, breadcrumbs, egg yolk, fennel seeds and some seasoning in a large bowl. Mix everything with your hands for about 5 mins until well combined, then roll the mixture into 12 balls. Heat the remaining oil in a large non-stick frying pan over a medium heat, and fry the meatballs for 5 mins until evenly browned. Set aside.

Brush the crust of the pizza with a little oil, then sprinkle over the polenta. Top the pizza with the meatballs, pressing them into the sauce and cheese a little, then scatter over the remaining mozzarella. Immediately slide the pizza tray onto the hot baking sheet and bake for 15-18 mins, or until the pizza is cooked through in the middle and crisp around the edges. Scatter over the parmesan and oregano, then slice into six squares to serve.