Baked Ham and Cheese in a Mashed Potato Crust

2 cups mashed potatoes (made with skim milk)
2 tablespoons prepared mustard
1/2 cup low-fat cottage cheese
1 pound cooked ham, cubed
2 slices low-fat Cheddar cheese, crumbled

Mix mashed potatoes and mustard. Spread evenly in bottom of nonstick 8-inch square baking pan. Add ham cubes in layer on top of potatoes. In electric blender, blend cottage cheese and Cheddar cheese until fairly smooth. Spread over ham. Bake at 350 degrees F for 30 minutes or until casserole is heated through.