In a large mixing bowl, blend together sugar, butter and egg. Beat until thoroughly blended.
Sift flour, baking powder and salt together.
Stir milk into sugar-butter-egg mixture.
Add dry ingredients to milk mixture and stir until thoroughly blended.
Spread batter into an 8-inch square, heat resistant, non- metallic baking dish.
Arrange apple slices in a design on top, pressing them slightly into the batter.
Combine cinnamon and sugar in a small bowl and sprinkle on top of apple slices.
Heat, covered with clear plastic wrap, 5 minutes in Microwave Oven. Uncover and heat an additional 4 minutes or until apples are tender and a toothpick inserted in center comes out clean.
Allow to stand 10 minutes before serving.