Melt margarine. Add flour and mix. Add cold water and mix. Separate into two balls. Spread dough on a greased 17x12-inch cookie sheet with hands (no rolling pin), until you have two 12x3-inch pieces
Cook margarine and water to a rolling boil. Take off heat and add flour and almond flavoring. Place back on heat and stir constantly until mixture forms a ball. Take off heat. Add eggs all at once. Beat until smooth and glossy. Spread evenly over first mixture. Bake at 350 degrees for 1 hour. Cool. Frost.
For frosting: Blend powdered sugar, water, vanilla until desired consistency is reached. Frost cooled pastry and sprinkle with chopped nuts.