Crust:
2 cups all-purpose flour
1/2 tsp salt
3/4 cup butter
3/4 cup cooked, mashed potatoes or 3/4 cup instant mashed potatoes and 3/4 cup water
Filling:
4 hard-cooked eggs, chopped
1 cup cooked rice
1 pound filleted fresh herring or smelts, or codfish or haddock fillets
1 1/2 tsp salt
1/2 tsp white pepper
2 Tbsp chopped fresh or dried dill weed
1/2 cup heavy cream
1 egg, beaten
Glaze
1 egg, beaten
Sauce
1/2 cup melted butter
1/4 cup chopped fresh dill or 2 Tbsp. dried dill weed
2 Tbsp fresh lemon juice
Measure the flour, baking powder, and salt into a mixing bowl or work bowl of food processor with te steel blade in place. With a pastry blender or fork, or using on/off pulses on the food processor, bend in the butter until the mixture resembles coarse crumbs. Gently mix in the cream; gather the dough together into a ball; wrap and refrigerate 30 minutes.
Preheat the broiler and place the salmon on a baking sheet covered with foil. Broil 5 inches from the source of heat for 5 minutes on each side, brushing both sides with the melted butter. Cool. Carefully cut the fish into 1/2 inch slices.
Mix the remaining butter with the rice; season with salt and fresh dill.
Cover a baking sheet with parchment paper. On a lightly floured board, roll out the dough to a rectangle and trim to measure 12x16 inches. Place on baking sheet. Spread half the rice mixture down a 3-inch-wide strip the length of the pastry. Top rice with fish slices. Top fish with the remaining rice. Lift pastry up over the filling, moisten the edges, and seal. Turn over so that seam side is down.
Mix the egg and water to make a glaze and brush pastry with the mixture. Decorate with the pastry trimmings cut into shapes and pierce pie with a fork to make steam vents.
Preheat oven to 400 degrees F. Bake for 25 to 30 minutes or until golden. Serve slices with a sauce made by mixing the melted butter, lemon juice, and fresh dill.