Discard any mussels with broken shells and any that refuse to close when tapped. Place the mussels, wine and 2 thyme sprigs in a large saucepan. Cover with a lid and cook for 3–4 minutes. Discard any mussels that remain closed and set aside the rest.
Heat a tablespoon of the oil in a frying pan and add the chorizo. Cook for 2–3 minutes, or until crisp. Remove from the pan and set aside.
Add the onion, garlic and the remaining thyme to the pan and cook for 4–5 minutes, or until soft. Return the chorizo to the pan and pour in the tomatoes. Cook until the volume of liquid has reduced by half. Stir in the mussels and parsley and season with salt and pepper.
Heat the remaining oil in a frying pan. Once hot, add the trout and fry on each side for 2 minutes, or until cooked through.
Divide the sauce between two warmed plates and top with a trout fillet. Serve immediately with the crusty bread.