How to Make It
Heat oven to 350°. Coat an 8-inch square baking dish with cooking spray; set aside.
Bring a large pot of water to a boil over high heat; add noodles, and cook 7 minutes or until al dente. Drain and set aside.
Reduce heat to medium; add margarine, and cook until margarine melts. Add flour, salt, and pepper; cook 1 to 2 minutes until flour begin to brown. Stir in milk, 1/2 cup at a time, whisking well to ensure a smooth sauce. Stir in cheeses; whisk until completely melted. Stir in cooked noodles. Transfer mixture to prepared baking dish.
Top noodles with breadcrumbs; bake at 350° for 20 minutes or until top begins to brown and cheese is bubbly.
While noodles bake, place roasted bell pepper and yogurt in a blender or food processor; process until smooth. Drizzle over squares of baked noodles and serve.