Melt margarine in a large nonstick skillet over medium heat. Add turkey and onion; saute 3 to 5 minutes or until turkey is browned. Add mushrooms; saute 1 minute.
Add flour to skillet; cook, stirring constantly, 1 minute. Gradually add milk, stirring constantly. Add peas and carrots and next 3 ingredients. Cook, stirring constantly, until mixture is thickened and bubbly.
To serve, spoon turkey mixture evenly over muffin halves; sprinkle with paprika. Serve immediately.