1/2 pound small red-skinned potatoes, quartered |
1/2 pound (1/2-inch) cubed peeled sweet potato |
1/2 tablespoon olive oil |
cooking spray |
3 tablespoons buttermilk |
1 tablespoon mayonnaise |
1/2 tablespoon finely chopped shallots |
1/2 tablespoon chopped fresh chives |
1/2 tablespoon dijon mustard |
1/4 teaspoon black pepper |
1/4 teaspoon salt |
1/4 cup chopped celery |