Precook broccoli (steam or microwave) until almost tender. In a skillet, break up chicken into bite-size pieces with 1 tablespoon margarine. Cook about 5 minutes. In a 9"x13" dish, place broccoli and melted butter and then chicken. Mix together soup, mayonnaise, lemon juice, curry powder, salt and pepper; place on top of chicken. Add topping of dressing and butter. Bake until bubbly, about 1 hour at 350°.