Potatoes and Eggs au Gratin

Cook whole potatoes, covered, in boiling salted water for 25 to 30 minutes or till almost tender; drain well. Peel and slice cook potatoes. {You should have about 3 cups.} Thinly slice the hard-cooked eggs; cut tomato into wedges. In a saucepan, cook chopped onion in 1 tablespoon butter or margarine till tender. Stir in flour. Stir in sour cream, shredded cheese, milk, parsley, paprika, 1 teaspoon salt, and 1/8 teaspoon pepper. Cook and stir over low heat until cheese melts. Combine sour cream mixture and sliced potatoes. Place half of the potato mixture in a 1 1/2-quart casserole. Top with egg slices and tomato wedges. Spoon remaining potato mixture atop. Toss bread crumbs with 1 tablespoon melted butter or margarine; sprinkle atop. Bake in a 350 degree oven for 40 to 45 minutes or till heated through. Garnish with additional tomato wedges, hard-cooked egg wedges, and parsley, if desired.