Make the pizza dough in the usual way (you can follow the instructions here)
Divide the dough into two discs, one larger than the other, wrap them in cling film and place in the refrigerator to rest.
Place a baking sheet in the oven and preheat it to 400º F.
Fry the sausage in olive oil and set aside to cool. Add all the other ingredients except the breadcrumbs and mix thoroughly.
Roll the larger dough piece over a 9-inch spring form tin, leaving a few inches overlap. Sprinkle breadcrumbs over the pastry lined tin, add the filling and cover with the rolled out smaller piece. Turn the edges of the overhand over to form a border.
Glaze the top of the pie with the milk, salt and egg mixture and stab with a fork to create steam holes. Place on the baking sheet and bake at 400ºF for ten minutes, then turn down the heat and cook at 350ºF for 45 minutes.
Take pizza out of the oven and allow to cool for up to 25 minutes before serving. Makes 8-10 servings. Nigella Lawson’s How to Become a Domestic Goddess’ cookbook is a great way for beginners to learn how to bake basic treats, as well as for veterans to polish up on their skill while creating delicious and decadent baked goods.