Heat oven to 350 degrees. Cut 1/2 cup butter into 1 cup flour until particles are the size of small peas. Sprinkle 2 tablespoons water over flour mixture; mix with fork. Gather pastry into a ball; divide into halves. Pat each half into a 12x3-inch long rectangle on an ungreased cookie sheet. Rectangles should be about 3 inches apart.
Heat 1/2 cup butter and 1 cup water to a rolling boil; remove from heat. Quickly stir in almond extract and 1 cup flour. Stir vigorously over low heat until mixture forms a ball, about 1 minute; remove from heat. Add eggs; beat until smooth and glossy. Spread half of the topping over each rectangle. Bake until topping is crisp and brown, about 1 hour; cool. (Topping will shrink and fall, forming the custardy top). Spread with powdered sugar glaze; sprinkle with nuts. Makes 2 Coffee Cakes (5 to 6 servings each)
Powdered Sugar Glaze: Mix 1 1/2 cup powdered sugar, 2 tablespoons margarine or butter and 1 1/2 teaspoon vanilla. Stir in 1 to 2 tablespoon warm water, 1 teaspoon at a time, until smooth and of desired consistency.