First make the tomato sauce if not using a ready-made version. Gently sauté the onion, garlic, celery and carrot over low heat for 10 minutes. Add the passata and sugar, then season to taste. Cook for about 20-30 minutes until the vegetables are soft. Taste and adjust the sweetness & seasoning. Using a hand-held blender, whizz it into a thick sauce, then set aside.
Finely chop the mushroom and garlic. Heat 1 Tbsp of olive oil in a saucepan and gently sauté the mushroom and garlic. Add the kale/spinach, and steam under a lid for about 5 minutes until the kale/spinach has welted. Mix in the chicken, let it cool. Mix in enough ricotta to have a thick filling. Add the cayenne and plenty of seasoning.
When you're ready to bake the dish, set the oven to 200°C.
Boil some water in a large saucepan. When it’s boiling slide in a few sheets of lasagne and blanche for 3-5 minutes, until al dente. Place the sheets onto a plate, add some stuffing, then roll them up. Meanwhile blanch the rest of the lasagne sheets.
Spoon a layer of tomato sauce in a deep baking dish. Place the rolls neatly and tightly next to each other then pour over the tomato sauce. Sprinkle with Parmesan and bake for 20-25 minutes until the top is golden.
Serve with a green salad.