Cook the spaghetti in plenty of salted water until al dente.
Chop the onion and fry in a little oil. Deglaze with the tomato puree, rinse the pack with a little water and add this to the sauce. Cut the Bavaria Blu (or another blue cheese) into cubes and add to the tomato sauce. Bring to the boil and let the cheese melt while stirring constantly.
Season with salt, pepper and fondor, or with chilli if you like, and stir in the cream. Bring to the boil and serve with the pasta.