Thaw the prawns and pat dry. Then roll in flour and fry in a pan with fat until crispy brown. Remove the prawns and set aside.
Cut the onion into cubes and fry in the pan until translucent. Then deglaze with the cognac and simmer briefly. Add the cream and season with salt, tomato paste, paprika powder, pepper and cayenne pepper. Reduce the sauce for a few minutes until creamy.
At the same time, cook the spaghetti in salted water until al dente and mix with the sauce and prawns in the pan.