Heat the olive oil in a heavy pan to medium high. Add the onions and cayenne pepper with a dash of salt. When the onions begin to show a little color, add the reminder of the salt and the shrimp.
Stir in the cut tomatoes, while still on the heat. Mix in and incorporate the cooked pasta with all the ingredients. Pour in the cream while stirring, followed by the nutmeg and vodka (or brandy); heat everything briskly, but without boiling. Lastly, stir in the 1/2 cup of parsley to wilt very slightly and then take off the heat to plate. Garnish with fresh parsley and a sprinkle of aleppo pepper, if you like.