1. Start oven, set at Moderate, 350° F. Rub a baking pan with margarine or butter.
2. Prepare the eel for cooking as described. Cut it in 1 1/2 or 2-inch slices. Season with salt.
3. Arrange the fish in the baking pan, dot with butter or margarine. Bake 30 to 45 minutes, or until tender.