העוגת דגים המושלמת

מצרכים

• 280g haddock fillets (10 oz)
• 150ml milk (2/3 cup)
• 50ml water (1/4 cup)
• 280g potatoes (10 oz)
• 1 tsp fresh parsley, chopped
• 1 tbsp fresh chives, chopped
• 1 egg
• 85g fresh breadcrumbs (3 oz / about 1½ cups)
• 125ml mayonnaise (½ cup)
• 1 tbsp capers, roughly chopped
• 1 tsp creamed horseradish
• 1 tsp Dijon mustard
• 1 small shallot, very finely diced
• 1 tsp fresh parsley, finely chopped