1Heat oven to 400°F. In 10-inch nonstick skillet, melt butter over medium heat. Stir in beef; sprinkle with seasoning mix (from dinner kit). Cook 10 to 12 minutes, stirring occasionally, until desired beef doneness; drain. Meanwhile, place refried beans in microwavable dish. Microwave uncovered on High 2 minutes, stirring once or twice.
2Spread beans over each tortilla (from dinner kit) to within 1/4 inch of edges. Top with beef, Cheddar cheese and onions. Roll up, folding in sides. Place seam sides down in ungreased 13x9-inch (3-quart) glass baking dish. Pour fajita sauce (from dinner kit) on top. Sprinkle with Mexican cheese blend.
3Bake 15 to 20 minutes or until burritos are hot and cheese is melted.