Preheat oven to 350. Heat oil in small nonstick skillet on medium-high heat. Add onions; cook 5 minutes or until onions are tender, stirring occasionally. Add broccoli; mix well. Spoon into 9-inch pie plate sprayed with cooking spray.
Mix remaining ingredients until well blended; over broccoli layer.
Bake 45-50 minutes or until center is set and top is golden brown.