Crisp Pork Medallions with Creamy Caper Sauce

Name: Crisp Pork Medallions with Creamy Caper Sauce
Ingredients: 2/3 cup plain yogurt (6 ounces; preferably whole-milk); 3 tablespoons mayonnaise; 2 tablespoons drained bottled capers, finely chopped; 1 tablespoon finely chopped fresh flat-leaf parsley; 1/8 teaspoon black pepper; 1 1/2 to 1 3/4 lb pork tenderloin; 3/4 cup all-purpose flour; 1 teaspoon salt; 1/4 teaspoon black pepper; 2 large eggs; 1 cup fine dry bread crumbs; About 1 cup vegetable oil for panfrying; Accompaniment: lemon wedges; watercress or other baby greens; an instant-read thermometer