Preheat your oven to 180 C.
Sprinkle the zucchini ribbons with extra salt and let them drain some water while you go on with the rest of the ingredients. The first and last slice of the zucchini, I cut into small cubes to use it in the ricotta filling.
Mix the ricotta homemade or shop-bought, 2 tsp salt, black pepper, parmesan cheese, thyme, lemon zest, zucchini cubes and egg in a bowl until well combined. Then roll the ricotta mix into small balls, depending on the size of your zucchini. You don't want the ricotta balls to be bigger than the slices of zucchini. Now grease your baking dish (I use a round one, 23 cm in diameter) with the olive oil.
Combine the tinned tomatoes, sugar, 1 tsp salt and 100 ml water. Pour the mixture into your baking dish.
Drain the zucchini ribbons under water to get rid of the salt. Pad them dry.
Lay 1 zucchini ribbon out in front of you and put 1 cheese ball onto the ribbon, right at the beginning. Now roll up the zucchini ribbon until you get to the end.
Put the filled cannelloni into the tomato sauce and continue with the remaining ingredients. By putting them tight together, you prevent the zucchini ribbon from opening up.
Pour the cream over the top (if you use it) and bake in the oven for 25 minutes.
Then scatter the mozzarella cheese on top and bake for another 15 minutes.
Enjoy with fresh ciabatta on the side.