Fish Pie with Mashed Potatoes (Irish)

Potato topped fish pies were a common Friday night dinner back in the "no meat on Fridays" and were obviously well liked enough that they have remained a staple of Irish home cooking, especially in coastal regions.

2 Tbsp. butter
2 onions, finely chopped
1 cup white sauce (240 mL)
1 tsp. dry mustard
1½ lb smoked haddock or finnan haddie or a combination of smoked haddock or finnan haddie and unsliced smoked salmon, cut into 1" (2.5 cm) cubes (750 g)
1 cup fresh peas, shelled (~ 1 lb (500 g)
sea salt
black pepper, freshly ground
2 cups potatoes, mashed (420 g)

Preheat the oven to 400°F (200°C/180°C fan, Gas Mark 6).

Melt the butter in a large saucepan over low heat, then add the onions and cook, stirring frequently, for 12-15 minutes or until soft, but not browned.

Remove the pan from the heat and stir in the white sauce, mustard, smoked fish and peas, mixing together well. Season to taste with salt and pepper.

Put the smoked fish mixture into a casserole or glass or ceramic baking dish, then spread the mashed potatoes on top. Season the top of the potatoes lightly with salt and pepper.

Bake for 40-45 minutes, or until the top of potatoes has turned golden brown.

Makes 4 servings.