Place potato in a saucepan; add water to cover, and bring to a boil. Cover, reduce heat, and simmer for 20 minutes or until very tender; drain well.
Combine potato, sour cream, and the next 3 ingredients in a bowl, and beat at medium speed of a mixer for 2 minutes or until smooth. Set aside.
Coat a large nonstick skillet with cooking spray, and place over medium heat until hot. Add the cabbage, corned beef, and caraway seeds, and sauté for 4 minutes or until cabbage wilts. Remove from heat; stir in dressing. Set aside.
Spread half of potato mixture in the bottom of an 11 x 7-inch baking dish coated with cooking spray; top with cabbage mixture, and sprinkle with 1 cup cheese. Spread remaining half of potato mixture over cheese, and top with remaining 1/4 cup cheese. Sprinkle with paprika. Bake at 350° for 40 minutes or until golden.
Make-Ahead Tips: You can assemble the casserole up to 8 hours ahead of time; cover and chill. Let stand at room temperature 30 mintues before baking.