Preheat oven to 325 degrees F (165 degrees C). Generously grease a 2-quart baking dish.
Arrange apple slices in an even layer in the baking dish. In a small bowl, mix together 1/2 cup sugar, cinnamon, and 1/2 cup pecans. Sprinkle mixture over apples.
In a medium bowl, mix together flour, 1 cup sugar, baking powder, and salt. In a separate bowl whisk together egg, evaporated milk, and melted butter. Pour milk mixture into flour mixture all at once, and stir until smooth. Pour mixture over apples, and sprinkle top with 1/4 cup pecans.