Wash pumpkin, dab dry, quarter and remove seeds. Cut the pumpkin into cubes. Peel onion and garlic and chop finely. Boil up the stock.
Heat 20 g fat in a wide saucepan, sauté chestnuts in it for about 2 minutes and remove. 2 tablespoons olive
Add rice and sauté briefly while stirring. Add wine and let it simmer.
Add some hot stock until the rice is covered and simmer until the rice has absorbed the stock. Add the hot stock again and again and let it simmer openly at low to medium heat until the risotto is creamy (30-35 minutes).
Stir from time to time.
Stir chestnuts and mountain cheese into the finished risotto, season with salt and pepper. Wash the sage, shake dry and pluck the leaves from the stalks. Heat 4 tablespoons of oil in a pan and fry the sage leaves until crispy.
Arrange the risotto in deep bowls. Spread sage leaves and oil on top.