In a medium sized pan add the butter and the cooked spinach, mix and heat it through, cut into very small pieces. Move it to a large bowl, add the ricotta, the egg, half the parmesan cheese, salt and pepper. Gently mix to combine.
Stuff each cannelloni tube with the ricotta mixture.
Place ¼-⅓ cup (50-60 grams) of white sauce on the bottom of a medium/large (10 inch/27 cm rectangle) baking pan, place the stuffed cannelloni tubes on top.
Pour the remaining sauce on top and sprinkle with the remaining parmesan cheese. Bake for approximately 20 minutes, raise the temperature to 425F (225C) or broil for about 5 minutes or until golden on top, let sit 5 minutes then serve. Enjoy!
FOR THE WHITE SAUCE
In a large pot on low/medium heat melt the butter, add the salt and flour and whisk until completely smooth, slowly add the milk stirring constantly until thickened.
Notes
Recipe Notes
For Parmesan it's best to use Parmigiano Reggiano or Grana Padano. If you prefer you can use more ricotta and less spinach or vice versa.If you use dry cannelloni tubes then pre boil until very al dente, let cool then stuff.
Storage
Cooked Cannelloni or Manicotti should be kept in the fridge, it will keep for 3-4 days. Uncooked it can be frozen in air tight containers or bags for 1-2 months.
To cook the frozen pasta
Place it in a baking pan and cover with desired sauce, cover the pan with foil and bake for approximately 35 minutes. Let stand 5-10 minutes before serving.