1. Preheat oven to 350° F (190°C). Grease and flour 9 x 5-inch (23 x 13-cm) loaf pan; set aside.
2. In a large bowl, beat margarine sticks and sugar with an electric mixer on high speed until light and fluffy, about 2 minutes. Add eggs, one at a time, beating well after each addition. Beat in lemon peel and salt. Gradually beat in flour on low speed just until blended. Evenly spoon into prepared pan.
3. Bake for 1 hour. Cover loosely with aluminum foil and bake for an additional 5 minutes, or until toothpick inserted in centre comes out clean. Cool for 15 minutes on wire rack; remove from pan and cool completely.