Preheat oven to 425 degrees F. Coat a 9-inch springform pan with nonstick cooking spray; set aside.
In a medium saucepan cook the asparagus, covered, in a small amount of boiling water for 2 minutes. Drain; set aside.
In a small bowl stir together the grated Parmesan and basil. Sprinkle a work surface with half of the mixture. Roll out pizza dough on the surface to a 12-inch square. Sprinkle with remaining Parmesan mixture. Using a rolling pin, gently press into dough by rolling over top.
Turn dough into prepared pan. Press dough up the sides of the pan, folding under edges as needed to form sides that are 2 inches high. Line dough in pan with a double thickness of foil. Bake for 8 minutes. Remove foil. Bake 5 minutes more. Remove from oven. Reduce oven temperature to 350 degrees F.
Meanwhile, in a small skillet cook bacon until crisp. Drain, reserving 1 tablespoon drippings. Crumble bacon; set aside. Cook onion in reserved drippings over medium heat until tender but not brown; drain.
In a medium mixing bowl stir together eggs, milk, salt, and nutmeg. Stir in crumbled bacon and onion. Toss together Swiss cheese and flour. Add to egg mixture; mix well.
Pour egg mixture into the dough-lined pan. Toss asparagus halves with the oil. Arrange asparagus in a spokeline pattern on top of egg mixture. Bake 35 to 40 minutes or until a knife inserted near the center comes out clean. Let stand 10 minutes before serving. Remove sides of pan to serve. Top with shaved Parmesan cheese, if desired. Makes 6 main-dish servings.