Preheat your oven: to 180°C / 350-375°F / Gas Mark 4-5.
Baking dish: spray a large baking dish with cooking oil and then set aside.
Chorizo sausages: place a large saute pan on the stove, add the sliced chorizo pieces and fry for 3-4 minutes. Once done, transfer the cooked chorizo to a paper towel lined bowl.
Pasta sauce: without rinsing or cleaning the pan, add the olive oil, diced onion, garlic, salt and pepper. Cook these for 1 minute, stirring as you go. Then turn the heat to low and add the tomato passata, diced tomatoes, tomato paste, Worcestershire sauce and dried parsley. Stir to combine and let simmer.
Pasta: read and follow the instructions on the fusilli to cook it in a medium saucepan of boiling salted water. When it cooks till al dente (Note 7) use a colander over the sink to drain the pasta and discard the water.
Combine: next add the sliced chorizo to the pasta sauce and stir to gently fold these in.
Pasta and sauce: then add the drained fusilli to the combined chorizo tomato sauce and stir till these are consistently mixed together.
Into baking dish: next transfer the combined pasta, chorizo and sauce mixture into the oiled baking dish. Use a saucepan to push the mixture into the corners and the back of the spoon to smooth the surface layer.
Cheese topping: sprinkle the mozzarella cheese over the top of the dish and follow this by sprinkling the tasty cheese over the top.
Oven bake: place the baking dish into the preheated oven on the middle shelf. Allow the pasta bake to cook uncovered for 10 minutes.
To serve: once the cheese has melted and turned golden brown use oven mitts to remove the baking dish and place it onto a heatproof surface. Garnish with fresh basil leaves and black pepper. Provide bowls, forks and spoons, portion and serve.