Cook pasta according to package directions. Drain.
Meanwhile, for sauce, in a medium saucepan cook onion and garlic in oil until onion is tender. Stir in flour, basil or oregano, and salt. Add 1 cup milk all at once. Cook and stir until thickened and bubbly. Cook and stir for 1 minute more. Stir in artichoke hearts, Parmesan or Romano cheese, and 1 tablespoon parsley; heat through. If necessary, stir in enough additional milk to make of desired consistency.
Spoon pasta onto individual plates or a large platter. Ladle the sauce over the hot pasta. If desired, sprinkle with additional snipped parsley and pepper and garnish with tomato wedges and parsley sprigs. Makes 4 side-dish servings.