Pour the vegetable oil into a large, deep, frying pan. Once shimmering, scatter in the pancetta. Cook until golden, then remove from the pan using a slotted spoon, leaving behind the oil. Add the chicken to the pan and sprinkle with salt and pepper. Cook until golden on all sides, around 5-6 mins. Remove from the pan and set aside.

Tip the onion and garlic into the pan and cook for 8-10 mins. Put the pasta on to boil at the same time. Scatter the flour into the onion and garlic mixture, and cook for 1 min. Pour in the cream and milk a little at a time, whisking between each addition, until you have a smooth sauce. Reserve a mugful of pasta water before draining.

Stir the mustard and cheddar into the sauce. Season well with salt and pepper, then stir in the cooked pasta, chicken, reserved pancetta and a good splash of pasta water – you want it to be quite saucy.

Stir in the spinach a handful at a time to wilt, then transfer everything to an ovenproof dish. Sprinkle with parmesan over the top and some more black pepper.

If you want to freeze this and bake it later, leave it to cool, wrap it well to keep frozen for up to three months. When you’re ready to cook, heat the oven to 190C/180C/gas 4. Bake for 20 mins, or if you’re cooking from frozen, cook for 1 hr until bubbling.