In a large pan add the mince and onion and cook until the mince has browned, then add the pepperoni, and stir through the mince until slightly cooked.
Place the mince mixture into a large bowl, add the tomatoes, cream cheese, tomato puree, herbs and salt, and stir all the ingredients together to mix.
Meanwhile, bring a large pan of water to the boil, and cook each lasagne sheet individually, until just flexible, I make the cannelloni straight after each sheet is cooked. In a large ovenproof dish add a little of the pasta sauce and spread over the base of the dish. To make the cannelloni, lay the lasagne sheet on a plate and place some of the mince mixture in the middle, then roll up and place into the dish. Do the same with all of the lasagne sheets.
Pour the rest of the sauce over the cannelloni, then top with the grated Cheddar and mozzarella.
Bake in a preheated oven for 25 minutes.
Leave to rest for approximately 10 minutes, as this helps hold it together better.