Eggplant Swiss Cheese Casserole

1/2 cup onion, chopped
1 tablespoon vegetable oil
6 ounce can tomato paste
1 3/4 cups water
2 teaspoons dried oregano
1/4 cup parsley leaves, freshly chopped or 2 tablespoons dried parsley flakes
1/2 teaspoon salt
1 large eggplant or zucchini
1 pound swiss cheese, sliced
1 1/2 cup dry bread cubes
1 cup parmesan cheese, grated

Sauté the onion in the oil in a saucepan until the onion is tender. Add the tomato paste, water, oregano, parsley and salt. Simmer over low heat for 10 minutes. Cut the eggplant (or zucchini) into 1/4 inch thick slices. Arrange one layer of eggplant slices in the bottom of a lightly oiled 13x9x2 baking pan. Pour on about 1/3 cup of the tomato sauce. Top with the swiss cheese slices. Add another layer of eggplant slices and pour on about 1/2 cup of the tomato sauce. Combine the rest of the sauce with the bread cubes and spoon over the eggplant. Sprinkle on the parmesan cheese. Bake at 325 degrees for about 25 minutes.