Preheat your oven to 350f (180c).
Boil your pasta in well salted water, undercooking by 2 minutes from package instructions. Drain and toss with the butter to stop it overcooking. You can have the pasta boiling while you start the bacon and chicken.
Season the cut chicken pieces well with salt and pepper and toss with the flour and set aside.
In a large fry pan heat a drizzle of olive oil over a medium-high heat and cook the bacon until crisp and golden. Remove with a slotted spoon, leaving the fat behind.
In the same pan cook the chicken for 2 minutes each side, it shouldn't be cooked all the way through but you want some color on it. Remove to a plate/bowl with a slotted spoon.
Still keeping the same pan cook the onions with a big pinch of salt on a medium heat, add a drizzle of olive oil if it is too dry. Cook for 3 - 4 minutes until softened and translucent.
Add the garlic and rosemary and continue cooking for 1 minute.
Add the tomato paste and mix in for 1 minute.
Pour in the tomato passata and cream, mix well and bring to a gentle simmer.
Add half (40 grams) of the finely grated parmesan and let it melt in.
Add the cooked bacon, salt and pepper and check seasoning before adding chicken in.
Add the chicken back in and let it gently simmer for 2 - 3 minutes.
In a large mixing bowl (or in a pan if it is big enough) mix the pasta and spinach through. The spinach will seem like a lot but it will wilt down in oven.
Pour into your baking dish, spreading it out into an even layer. Sprinkle the mozzarella and remaining 40 grams parmesan in an even layer on the top.
Bake in the oven for 20 - 25 minutes until the top is lightly golden brown. You don't want to cook it longer than this as it can dry out.
Allow to stand for 5 - 10 minutes then sprinkle with the parsley and serve.
This is quite a saucy pasta bake, I hate a dry one! It's perfect for dunking some bread into!