This lightened-up creamy chicken casserole is packed with veggies. The sauce at the heart of this family-friendly casserole uses fat-free milk with a combination of fat-free Greek-style yogurt and a little mayonnaise to give it body.
Prepare broccoli in microwave according to package directions.
Heat a large ovenproof skillet over medium-high heat. Add oil to pan; swirl to coat. Add onion and mushrooms; cook 12 minutes or until mushrooms brown and liquid evaporates, stirring occasionally. Sprinkle mushroom mixture with flour; cook 1 minute, stirring constantly. Stir in milk. Bring to a boil; cook 3 minutes or until thick and bubbly. Stir in broccoli and chicken; cook 1 minute. Remove pan from heat. Stir in yogurt, mayonnaise, pepper, and salt. Top evenly with cheeses; broil 2 minutes.