In a large stockpot, heat the butter over medium heat. Add the shallots and cook until softened and translucent. Add chorizo and cook for another five minutes. Add water, stock, wine, saffron threads, parsley salt and pepper and bring to a boil.
Add the mussels, stir well, then cover the pot and cook over a medium heat, about 8 minutes, until the mussels are opened. Make sure the mussels are stirred through well. Discard any unopened mussels.
Pour into a large bowl and serve hot. These can be added to Paella or just served alone with lots of crusty bread. Delicious!
Notes
Of course you dont have to use Veuve Cliquot, however, I would recommend a dry sparkling over a sweet.