Preheat oven to 350°.
Slice apples about ¼ inch thick and place into large mixing bowl and set aside.
Combine the granulated sugar, flour, nutmeg, and cinnamon in a bowl and then pour it over the apple slices. Mix until all slices are covered.
Spread apple mixture in a 13x9 baking dish.
In a separate bowl, combine all the dry oat mixture ingredients. Cut the softened butter into the mixture until butter pieces are pea-sized or smaller. Pour the oat/butter mixture over the apple slices.
Bake for 45 minutes or until edges bubble.
