Arrange potato halves in a circle on paper towels in microwave oven. Microwave at HIGH 5 minutes or until tender.
Melt butter in a saucepan over medium heat. Add flour, stirring with a whisk. Gradually add milk and broth, stirring with a whisk. Cook over medium heat until thick, stirring constantly. Add potato and peas; bring to a boil, stirring to coat. Stir in pepper and mint.