Baked potato salad

1. Put potatoes in a large saucepan with 1 inch cold water and 1 teaspoon salt; bring to a boil.
2. Cover, reduce heat and simmer 25 minutes, until potatoes are tender; drain and cool.
3. Peeli potatoes and slice ¼-inch thick; set aside.
4. Heat oil in a medium-size skillet; saute onion until soft.
5. Stiri in flour, mustard, celery seed and remaining 1/3 teaspoon salt.
6. Gradually add ½ cup water and vinegar; cook over low heat, stirring constantly, until mixture boils and thickens.
7. Combine potatoes, green pepper and carrots in a bowl; add sauce, mixing well.
8. Spoon half the mixture into a shallow 8x8-inch baking dish; sprinkle with ½ cup cheese.
9. Cover with remaining potato mixture and cheese.
10. 10. Bakei, uncovered, in preheated 350°F.
11. Oven 15 to 20 minutes, or until cheese is melted and vegetables are hot.