Preheat oven to 400ºF. Grease an 8-inch round baking pan; set aside. In a medium mixing bowl combine flour, oats, sugar, baking powder and salt. In a 1-cup measure stir milk, oil and egg; pour all at once into flour mixture. Stir just until moistened (batter will be lumpy). Fold in blueberries; spoon batter into prepared pan. Bake until cake is golden and pulls away from sides of pan 20 to 25 minutes. Cool on a rack, 5 to 10 minutes. Serve warm.