In a medium heavy skillet, sauté meat of choice and onions over moderate heat until meat is lightly browned and onions crisp tender, breaking-up meat and stirring frequently. (Lightly coat skillet with non-caloric vegetable cooking spray if cooking ground chicken or turkey.) Drain off pan drippings. Add Italian seasoning or herbs, salt, and pepper, mixing well. Remove from heat and set aside.
With a pastry brush, lightly coat each tortilla, both sides, with oil. Arrange tortillas on ungreased baking sheets; bake in a preheated hot oven (400 degrees F.) for 3 minutes.
Evenly divide meat mixture onto the tortillas (on baking sheets). In order, top each tortilla with chopped tomato, fresh basil, mozzarella cheese, and Parmesan cheese. Return tortillas to oven and continue to bake (400 degrees F.) for 12 to 14 minutes or until mozzarella cheese is melted and Parmesan cheese is golden brown. Garnish each with a sprig of fresh basil and serve immediately.
Variations: Reduce amount of ground beef or Italian sausage to 8 ounces and add 1 cup miniature pepperoni sausage pieces to pizza filling. Sauté ½ to ¾ cup thinly sliced or coarsely chopped mushrooms with the ground beef or sausage and onions.