1Heat oven to 400°F. Grease bottom only of 8-inch square pan with shortening or cooking spray. In medium bowl, stir together Muffin Mix, apple, carrot, walnuts and coconut. In small bowl, stir together oil, eggs and pineapple; stir into muffin mixture. Spread in pan. Sprinkle with Streusel (from Muffin Mix).
2Bake 38 to 42 minutes or until toothpick inserted in center comes out clean. Cool 15 minutes.
3In small bowl, mix powdered sugar and enough of the 1 to 2 teaspoons water until smooth and thin enough to drizzle. Drizzle over warm cake.