BBC Food - Recipes - Salmon gravadlax with champagne mustard

Ingredients

• 50g/1¾oz caster sugar
• 75g/2½oz salt
• 1 tbsp pink peppercorns
• 1 tbsp coriander seeds
• 2 large bunches fresh dill , leaves chopped
• 1 large salmon fillet, skin and and pin bones removed
• 2 tsp Dijon mustard
• 1 tsp juniper berries
• 10g brown mustard seeds
• 75g/2½oz yellow mustard seeds
• pinch dark soft brown sugar
• 50ml/2fl oz red wine vinegar
• sea salt and freshly ground black pepper
• 75ml/2½fl oz champagne
• pumpernickel bread , to serve (optional)