Wipe filet of sole well. Melt 4 tablespoon butter in a small skillet; saute mushrooms until lightly browned. Remove from heat; stir in crab or shrimp meat, cracker crumbs, capers and dill weed. Spoon mixture onto center of filet of sole, distributing evenly, and roll, skewering with toothpicks. Place in large skillet. Sprinkle with seasoned salt; add lemon slices, wine and water. Cover and poach 20 minutes. Remove fish filets and lemon to a heated serving platter. Stir cornstarch into cream. Blend into pan juices until thickened. Beat egg in a small bowl; beat in a little hot mixture. Return to skillet stirring constantly until blended. Serve over fish at once.