1. Heat oven to 400 degree F.
2. In a large bowl, mix flour, sugar, and baking powder. Add berries and stir to coat them.
3. In another bowl, beat egg, milk, and oil together. Add to flour mixture, stirring only until ingredients are moistened.
4. Spoon mixture into buttered and floured tins. Bake about 25 minutes for regular-size muffins, 35 to 40 minutes for extra-large muffins. Muffins are done when a toothpick inserted in center comes out clean.