Combine oats, 3/4 cup raisins, baking powder, cinnamon, and salt and set aside.
In separate bowl, whisk eggs, milk, maple syrup, vanilla, and melted butter and stir into oat mixture.
Add chopped apple, stir, and pour into a greased 8" baking dish.
Sprinkle remaining 1/4 cup raisins on top.
Bake at 350-degrees for 45 minutes. Let cool slightly and cut into squares. Makes about 9 servings.