Have your butcher bone and trim a shoulder of lamb ready for rolling. Do not have him roll this.
Brush lamb with olive oil and sprinkle with salt and freshly ground black pepper, to taste. Sprinkle with lemon juice.
Combine the following ingredients in a large mixing bowl: sausage meat, finely chopped onion which you have sautéed in butter until transparent, finely chopped parsley, beaten egg, sautéed spinach, and salt, freshly ground black pepper and spices, to taste. Mix well. Lay this stuffing on meat; roll up and sew up with fine string.
Dust the lamb roll with flour; place it in a roasting pan with