1Heat oven to 375°F. Spray 9-inch square pan with cooking spray. In pan, mix broccoli, corn, onion and walnuts.
2In medium bowl, stir all remaining ingredients except cheese with wire whisk or fork until blended. Pour into pan.
3Bake 23 to 25 minutes or until knife inserted in center comes out clean. Sprinkle with cheese. Bake 2 to 3 minutes longer or until cheese is melted. Cool 30 minutes. To serve, cut into 5 rows by 3 rows; cut each rectangle diagonally in half.