In a lightly greased a 9 inch (23 cm) quiche dish or deep dish pie plate, evenly sprinkle broccoli, corn, onion and cheese. In a medium bowl, whisk eggs until blended. Add milk, baking mix, salt and pepper and whisk until thoroughly combined. Pour over broccoli mixture. Bake in a preheated 190° C (375° F) oven for 30 to 35 minutes or until a knife inserted near the centre comes out clean. Let stand for 5 minutes before serving.