To make the cheese sauce, melt the butter in a saucepan and stir in the flour. Remove the pan from the heat and add the milk. Stir over a medium heat and bring to the boil. Simmer for 8-10 minutes until it begins to thicken. Add the cheese and season with salt and pepper.
Chop up the sausages into small pieces and fry in a little oil in a large frying pan over a medium-high heat. Add the tomato sauce and bring to the boil. Add the oregano, season with salt and pepper and simmer for 10 minutes.
Cook the pasta for 2 mins less than package instructions.
Pour a kettle of boiling water over the spinach to wilt.
Add the pasta to the cheese sauce.
In a large dish, add the meat sauce and then the spinach, cover with the cheesy pasta mix and top with the parmesan.