Savory pies of every description are hugely popular in the British Isles. This creamy scallop pie simmers and bubbles beneath a blanket of flaky crust. A hint of onion and dry white wine makes this pie especially delicious.
FOR THE PASTRY: Cut shortening into flour and salt until particles are size of small peas. Sprinkle in water , 1 tablespoon at a time, tossing with fork until all flour is moistened and pastry almost cleans sides of bowl. Gather pastry into a ball; shape into flattened round. Wrap in plastic wrap.
PREPARE FILLING; If scallops are large, cut into 1 inch pieces. Cook and stir mushrooms and leek in 2 tablespoons of the margarine in 10 inch skillet over medium heat until mushrooms are light brown and liquid is evaporated, about 5 minutes. Remove from skillet. Heat 2 tablespoons of the margarine in skillet until hot. Cook and stir scallops over medium heat until white, 4 to 5 minutes. Remove with slotted spoon. Drain liquid from skillet, reserving 2 tablespoons.
Heat remaining 1/4 cup margarine in skillet over low heat until melted. Stir in flour, salt, mustard and pepper. Cook over low heat, stirring constantly, until smooth and bubbly. Remove from heat; stir in half and half. Add enough wine to reserved scallop liquid to measure 1/3 cup; stir into half and half mixture. Heat to boiling stirring constantly; boil and stir 1 minutes. Stir in mushroom mixture and scallops. Pour into ungreased shallow 1 1/2 quart casserole.
Heat oven to 425°F Unwrap pastry and place on well floured board. Roll dough 1 inch large than top of casserole, using floured stockinet covered rolling pin. Cut out designs with 1 inch cookie cutter. Place pastry over top of casserole; turn edges under and flute. Mix egg yolk and water; brush over pastry. Bake until golden brown, about 25 minutes. Serve with lemon wedges if desired. 4 servings.