PIE: 1 cup frozen peas 4 hard boiled eggs , quartered (optional) 30 g / 2 tbsp butter , melted 1/4 cup / 15g grated parmesan cheese , optional Finely chopped parsley , for garnish
POTATO TOPPING: 750 g / 1.5 lb floury potatoes , peeled and cut into 2.5cm / 1" pieces 30 g / 2 tbsp+ unsalted butter 1/2 cup / 125 ml milk, any fat %
WHITE SAUCE: 3 cups milk 50 g / 3 tbsp unsalted butter 2 garlic cloves , minced 1/2 small onion , finely chopped 1 small carrot , finely chopped 1 small celery stick , finely chopped 1/3 cup / 50g plain flour (all purpose flour, 1 tbsp fresh tarragon , finely chopped 2 tbsp parsley , finely chopped Salt and pepper
Preheat oven to 180C/350F. Boil water for potatoes.
Melt butter in a large, deep skillet or pot over medium high heat. Add onion and garlic, cook for 1 minute. Then add celery and carrot, cook for 5 minutes until carrot is soft.
Turn heat down to medium low. Add flour, mix in - it will look gluey.
Add half the milk and quickly start mixing. Once incorporated, the mixture will thicken quickly. Add remaining milk and stir.
Turn heat up to medium and keep stirring until the mixture thickens to the consistency of honey - about 3 minutes.
Take it off the heat, stir through tarragon and parsley. Adjust salt and pepper to taste.
Scatter top of flaked fish with peas, then pour over the Sauce. GENTLY stir through (don't want fish to turn into mush!).* Smooth top, then nestle egg in all over the pie.
Bring a large pot of water to the boil. Add potatoes and cook for 15 minutes or until soft. (Do this while making the Sauce). Drain potato, add butter, milk, salt and pepper. Mash until creamy - add more milk if required. Immediately dollop then spread onto pie (cold mash = hard to spread). Use fork to draw squiggles on surface (rough surface = better golden bits).
Drizzle surface with melted butter, sprinkle with parmesan.
Bake for 35 minutes or until top is deep golden. Stand for 5 minutes before serving, garnished with parsley if desired.