Cut 200 g of the pumpkin into rough cubes and steam with 50 ml of water until soft (about 15 minutes), puree and let cool.
Whisk the pumpkin puree with egg and add oil, salt and flour to make a soft dough.
Boil water in a large pot, add a little salt and press the dough through a spätzle sieve. Boil the spaetzle briefly, then drain in a colander.
Peel the onion, chop with the remaining pumpkin and roast in a pan.
Coarsely chop the pumpkin seeds and fry briefly, then add the spaetzle. Finally, chop the cheese, stir in and season with pepper.