Preheat the oven to 350°F. Cook the pasta according to the instructions on the package. Drain, reserving a couple of tablespoons of the cooking liquid, and return to the pan. Meanwhile, place the spinach in a large pan with the vegetable stock and cook until it wilts. Drain, squeezing out as much liquid as possible, and set aside.

In a large frying pan, gently cook the onion in the oil until soft but not colored.  Pour into a food processor, add the cooked spinach and parsley, and process to a smooth green purée. Add the soft cheese and eggs and process quickly to blend.  Scoop the spinach mixture into the pan with the pasta, add the peas and chile (if using), and mix thoroughly to combine. Season well with plenty of salt and black pepper. Pour into a baking dish, top with the shredded cheese, and bake in the oven for about 45 minutes until golden. Serve with a tomato salad.