Heat oven to 350°F. Spray 9-inch pie pan with nonstick cooking spray. In large saucepan, heat milk until very hot but not boiling.
Meanwhile, in small bowl, beat eggs and mustard until well blended. Add onion, cheese and pimientos; mix well.
Stir broccoli and rice into hot milk. Slowly add egg mixture, stirring constantly. Pour into sprayed pan.
Bake at 350°F. for 30 to 35 minutes or until knife inserted in center comes out clean. Let stand 5 minutes before serving.