For the pickling process: Bring eschallots, water, vinegar and sugar to a boil in a small saucepan. Simmer until soft. Drain.
Heat a small heavy based frying pan until very hot. Cook chorizo for about 3 minutes or until golden brown. Stir in eschallot mixture and parsley. Add cider. Deglaze until almost evaporated.
Serve chorizo in a clay pot with extra parsley.