Preheat oven to 400°. Heat large nonstick skillet over medium heat until hot. Add ground beef and onion; cook 8 to 10 minutes, breaking into small crumbles and stirring occasionally. Remove from skillet with slotted spoon; pour off drippings. Return beef to skillet; season with salt and oregano. Lightly brush tortillas with oil. Place on 2 ungreased large baking sheets. Bake in 400° oven 3 minutes. Spoon beef mixture evenly on tortillas; top with tomato. Sprinkle with basil, then with cheeses. Bake 12 to 14 minutes or until tortillas are lightly browned and cheeses are melted.
Recipe provided by The Beef Checkoff.