Crust: Combine macaroni, eggs and cheese. Spread over bottom of greased 20 cm (8 inch) square baking dish. Set aside.
Filling: In large skillet, heat oil on medium high heat. Stirfry onion, seeded tomato and mixed vegetables until tender crisp. Season with garlic powder, basil and oregano. Pour over macaroni crust.
Topping: In medium bowl, beat together eggs, milk, salt, pepper, and dry mustard. Stir in cheese. Pour over vegetable mixture. Bake in 180°C (350°F) oven for 25 to 30 minutes.