Par boil the pasta for around two thirds of the recommended time, cool under running water. This should give a 'al dente' pasta that can be stuffed with too many breaking.
In a large mixing bowl stir together the Ricotta, Spinach, Mozzarella, egg, basil and salt and pepper
Add a layer of tomato sauce to the base of a 12 x inch baking dish
Stuff each pasta shell with a tablespoon or two of the ricotta mixture. Keeping hands wet during this process can reduce the amount of mess!
Arrange the shells in a single layer on top of the tomato sauce
Cover with the remaining sauce and and bake covered in a layer of tin foil for 25 minutes
Remove the tin foil and bake until the top begins to brown, serve with fresh bread for a simple meal