Beat together oil and sugar. Mix in eggs, milk, salt, baking powder, oatmeal. Beat well then stir in raisins. Pour into a lightly grease pie pan. Sprinkle with brown sugar and cinnamon. Refrigerate overnight.
The next morning, preheat oven to 350 degrees F (175 degrees C).
Bake in preheated oven until firm, about 35 minutes. Serve hot.