Fantastic fudge squares

Ingredients

Squares :

• 1/2 Cup Margarine
• 1 Cup Brown Sugar
• 1 Egg
• 1/2 teaspoon Salt
• 1/2 teaspoon Vanilla
• 1 Cup Flour
• 1 teaspoon Baking Powder

Icing :

• 1/4 Cup Butter
• 1/2 Cup Brown Sugar
• 2 tablespoons Milk
• 3/4 Cup Icing Sugar