Roll the dough to a 12-inch square and place on paper-lined sheet pan. Mark dough into 3 strips, each 4 inches wide and 12 inches long. Slash the two outermost strips diagonally at 1/2-inch intervals, making downward slashes. Spread the filling on the center strip. Fold the slashes over the center strip, alternating a slash from each side. Proof 50%. Brush the egg white on the pastry and strew with the sliced almonds. Bake it at 400 degrees about 15 minutes. Cool and drizzle with warm water icing.