1Heat oven to 400°F. Spray 9-inch glass pie plate with cooking spray. Layer broccoli, 1/2 cup of the cheese, the chicken and onion in pie plate.
2In medium bowl, stir Bisquick mix, milk, salt, peper and eggs with wire whisk or fork until blended. Pour into pie plate.
3Bake 20 to 25 minutes or until knife inserted in center comes out clean. Sprinkle with remaining 1/2 cup cheese. Bake 3 to 4 minutes longer or just until cheese is melted. Cool 5 minutes.