Mashed potato fish casserole Recipe

Ingredients

• 4 hake steaks (about 800 grams (1 3/4 pounds))
• 1 medium onion
• 50 ml (1/4 cup) olive oil
• 1 teaspoon paprika
• Coriander (to taste)
• 1 egg yolk
• 250 ml (about 1 cup) milk
• Juice of half a lemon
• Pepper (to taste)
• Zest of a lemon
• Salt (to taste)
• 1 kg (2 1/4 pounds) potatoes
• 1 tablespoon margarine
• Juice of one lemon
• Nutmeg (to taste)
• 400 ml (1 3/4 cups) milk