Directions

1. Preheat broiler. Brush a baking sheet with oil; set side. Place the potatoes and 1/4 cup water in a microwaveable dish, cover with plastic wrap, and cook on high until potatoes are easily pierced with the tip of a sharp knife, 8 to 10 minutes. (Alternatively, place potatoes in a medium saucepan, cover with water, and bring to a boil; simmer until fork tender, about 20 minutes.) Rinse under cold water until cool enough to handle. Cut into 1-inch chunks, and place in a medium bowl.
2. In a large bowl, whisk together vinegar, mustard, and 1/4 teaspoon each, salt and pepper. Slowly add 1/4 cup oil, whisking to emulsify. Pour dressing over potatoes, toss to combine and set aside.
3. In a shallow bowl, whisk the egg with 1/4 teaspoon each salt and pepper. Place the breadcrumbs in a second shallow bowl. Slice the cheese into 8 rounds, and pat each into a disk about 1/2-inch-thick. Cover with wax paper to prevent sticking. Using two forks, dip disks first in egg, and then in the breadcrumbs, coating evenly. Place on prepared baking sheet.
4. Brush disks lightly with the remaining 1/4 cup oil, and broil until golden and crisp, about 5 minutes.
5. Toss the lettuce with the dressed potatoes. To serve, spoon salads onto plates, and top each with cheese disks.