Seafood casserole

Ingredients

• 3 tbsp olive oil
• 1 large onion finely sliced
• 4 carrots diced
• ¾ cup zucchini diced
• 2 celery stalks thinly sliced
• Salt to sufficient quantity
• tbsp maida
• ¼ cup fish stock
• 1 cup cream
• Salt and black pepper powder to sufficient quantity
• ½ kg thick-skinned fish, cleaned, diced and cooked
• ½ kg prawns, cooked after cleaning and removing shell and vein
• 3 potatoes skinned, boiled and mashed
• ¾ cup bread powder
• ¼ cup cheese grated
• A little butter