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.