Clean, wash and drain the chard. Cut the leaves from the panicles. Chop the leaves and panicles into medium-sized pieces. Peel garlic and chop finely. Heat the oil in a pan and sauté the chard in it. Add garlic and season with salt, pepper and nutmeg. Remove and mix with the ricotta.
Fill the cannelloni with the chard and ricotta mixture. Place in an ovenproof dish (28x15 cm, 1 litre capacity) and sprinkle with the Parmesan cheese. Pour on the stock and cook in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 30 minutes. In the meantime wash the thyme, dab dry and pluck. Coarsely chop the walnuts. Heat butter in a pan, brown lightly, add nuts and thyme. Arrange cannelloni on plates and sprinkle with the nut butter