Cut apple in half lengthwise. With spoon, remove and discard core, making at least a 1-inch indentation in each apple half. Place each half in small microwave-safe bowl.
Fill each apple half evenly with raisins and brown sugar; dot with margarine. Cover each with microwave-safe plastic wrap, venting one corner.
Microwave each apple half on HIGH for 2 1/2 to 3 minutes or until apple is tender. Top each with granola. If desired, serve with a little milk, cream or fruit-flavored yogurt.