Heat oil in a large casserole over medium-high heat, add onion and garlic and sauté until soft and starting to colour (5-7 minutes). Add chorizo, stir occasionally until coloured (3-5 minutes), then add tomato and cook until slightly thickened (3-5 minutes). Add vinegar and stir to combine. Drain clams, rinse well, add to casserole, add cider, cover and cook, shaking pan occasionally until all clams open (3-5 minutes). Stir through parsley, season to taste and serve hot with crusty bread.
This recipe is from the October 2009 issue of Australian Gourmet Traveller.