Apple Coffee Cake

• 1 ½ cups all-purpose flour sifted
• 2 teaspoon baking powder
• ¼ teaspoon salt
• ¼ cup margarine
• ¾ cup sugar
• 1 egg
• ½ cup milk
• 1 teaspoon vanilla

Topping

• 1 ½ TBS margarine
• ⅓ cup sugar
• 1 teaspoon cinnamon
• 2 apple peeled, cored, and sliced, medium