Combine first 3 ingredients in a nonstick skillet; cook over medium-high heat until meat is browned, stirring until it crumbles. Drain and pat dry with paper towels. Wipe drippings from skillet with a paper towel.
Melt margarine in skillet over medium-high heat. Add carrot and red pepper, and saute until crisp-tender. Add flour; cook, stirring constantly, 1 minute. Gradually add broth and next 4 ingredients. Bring to a boil; reduce heat, and simmer 10 minutes, stirring occasionally. Return meat mixture to skillet; stir well. Stir in peas. Spoon meat mixture into an 8-inch square baking dish coated with cooking spray.
Cook frozen potato in skim milk according to package directions. Spread potato over meat mixture. Top with cheese. Bake at 400° for 30 minutes or until golden and bubbly.