1Heat oven to 400°F. Grease 9-inch glass pie plate with shortening or cooking spray. In large bowl, mix broccoli, 1 cup of the cheese, the chicken and onion. Spoon into pie plate.
2Stir eggs, milk, Bisquick mix, salt and pepper until blended. Pour over mixture in pie plate.
3Bake 30 to 35 minutes or until knife inserted in center comes out clean. Sprinkle with remaining 1/2 cup cheese; bake 1 to 2 minutes longer or just until cheese is melted. Cool 5 minutes before serving.