1 heaped tbsp chopped fresh parsley
1 red onion, sliced
1 ripe tomato, finely sliced
1 tbsp small capers, drained
1 tbsp plain flour
4 whole sardines, cleaned, heads removed
2 tsp wholegrain mustard
freshly ground black pepper
1 tbsp caster sugar
3 tbsp olive oil
2 tbsp red wine vinegar
flaked sea salt
50驳/1戮辞锄 butter, softened
4 slices sourdough bread