Heat 1 inch salted water (1/2 teaspoon salt to 1 cup water) to boiling. Add broccoli. Cover and heat to boiling. Cook until stems are almost tender, 10 to 12 minutes; drain. Place broccoli in ungreased 1 ½ quart round casserole.
Heat oven to 400 degrees. Beat soup and milk with hand beater until smooth; pour over broccoli. Sprinkle with cheese. Mix baking mix and margarine until crumbly; sprinkle over cheese. Bake until crumbs are light brown, about 20 minutes.
Yield: 6 to 8 servings