• In a large bowl, cream margarine. Add remaining ingredients. Beat until smooth and of spreading consistency.
• If necessary, thin with additional milk or thicken with additional powdered sugar. Frosts 13×9-inch loaf cake or 2 layer cake.

Variations:

• Brown Butter Frosting: Brown margarine in large saucepan over medium heat until light golden brown. Blend in remaining ingredients, beat until smooth.
• Chocolate Butter Frosting: Blend in 1/3 cup cocoa, 2 envelopes premelted unsweetened baking chocolate flavor, or 2 1-ounce squares melted unsweetened baking chocolate into creamed margarine.
• Chocolate-Cherry Butter Frosting: Blend 3 tablespoons drained, chopped maraschino cherries into Chocolate Butter Frosting.
• Coffee Butter Frosting: Add 1 1/2 teaspoons instant coffee with the sugar. The coffee may be dissolved in the milk for a smooth, no fleck appearance.
• Mocha Butter Frosting: Blend in 3 tablespoons cocoa and 1 teaspoon instant coffee into creamed margarine.
• Cream Cheese Frosting: Substitute a 3-ounce package of cream cheese for margarine.
• Nut Butter Frosting: Blend in 1/4 cup chopped nuts to frosting.
• Orange or Lemon Butter Frosting: Substitute 1 teaspoon grated orange or lemon rind for vanilla and 2 or 3 tablespoons orange or lemon juice for the milk.
• Peanut Butter Frosting: Cream 3 tablespoons peanut butter with the margarine.