Put the spinach, mozzarella cheese, ham, and the milk in a blender and mix it all together.
Stuff the cannelloni tubes with the paste, and place them in a oven form.
Start the oven at 220 degree Celsius.
Pour the tomato sauce on top of the cannelloni.
Grate and sprinkle the cheese on top of the cannelloni.
Put the form in the middle of the oven for 25-30 minutes.
Take the cannelloni out from the oven and serve warm.