Heat a large nonstick skillet over medium-high heat.
Cut the tenderloins diagonally across grain into (1-inch-thick) slices. Pound each slice using a meat mallet or rolling pin to 1/2-inch thickness. Combine 1/2 cup broth, wine, and the next 5 ingredients (wine through pepper). Combine remaining broth and cornstarch, stirring with a whisk.
Melt butter in pan over medium-high heat. Add turkey; cook 3 minutes. Turn turkey over, and cook 1 minute. Remove from pan. Add shallots and rosemary; cook 3 minutes, stirring constantly. Add wine mixture, and bring to a boil. Cook 2 minutes. Add cornstarch mixture; boil 1 minute. Serve sauce with turkey.