Oven Method: Place blueberries in a lightly oiled or nonstick-sprayed 2-quart casserole dish. Sprinkle with lemon juice and cinnamon and stir. In a small bowl, combine brown sugar, oatmeal, cornmeal and oil. Spread over blueberries. Bake at 300 for about 50 minutes or until brown.
Stove Top Method: In a small saucepan combine oatmeal, cornmeal and oil. Cook over medium heat for a few minutes. Add brown sugar and cook until grains are lightly browned, stirring frequently. Place blueberries in the bottom of a large, lightly oiled or nonstick-sprayed skillet. Sprinkle with lemon juice and cinnamon, stir and heat through. Spread the oatmeal mixture over the fruit, cover and heat for a few minutes, then serve.