Peel and finely chop the onion. Melt the fat in a pot. Fry diced onions in it until transparent, turning them over. Deglaze with stock and milk. Cut cheese into cubes and stir into the sauce, except for something to garnish.
Season with salt, nutmeg and pepper. Simmer at low heat stirring several times for about 10 minutes. Prepare pasta in boiling salted water according to package instructions.
In the meantime, clean the chilli, cut lengthwise, wash and remove the seeds. Cut 1/2 pod into small pieces. Use the rest for other purposes. Wash and clean the pumpkin and cut into small pieces. Leek onions clean, wash, shake dry and cut into small rolls.
Clean radicchio, remove stalk. Cut radicchio into strips. Heat oil in a frying pan. Fry the pumpkin for about 2 minutes while turning. Add spring onions, radicchio and chilli and fry vigorously for about 1 minute.
Season to taste with salt, sugar and pepper.
Pass the sauce through a sieve. Drain the pasta. Collect 100 ml cooking water. Put the noodles with the cooking water and sauce back into the pot and mix. Arrange on plates with the vegetables. Crumble the rest of the gorgonzola over them.