Preheat oven to 350° F.
Prepare pastry base: Cut butter into flour until it resembles coarse crumbs. Sprinkle water over mixture, and mix well. Shape dough into a ball; divide ball in 1/2. Pat each half into a 13-inch strip on an ungreased baking sheet (place strips 3 apart). Set aside.
Prepare pastry top: Heat butter and water to a rapid boil in a medium saucepan. Remove from heat and quickly stir in the flour and extract. Stir vigorously and cook over low heat until mixture forms a ball (about 1 minute). Remove from heat. Add eggs, and beat until smooth and glossy. Divide topping in 1/2, and spread over prepared dough strips (pastry base).
Bake in a 350° F oven for 1 hour, or until the top is crisp and slightly browned.
When cooled, drizzle with a thin glaze of powdered sugar mixed with milk or water. Sprinkle lightly with chopped nuts.
Servings: