Well, for a cooking contest you will want to apply your own innovation to a classic or create a new dish that marries innovative flavors or features new ingredients.
I was going to say eggplant parmesan, but several people beat me to it. I’d make some creamy mashed potatoes (possibly with garlic or rosemary) to go with it, and maybe some roasted brussels sprouts on the side. Mmm, mouth watering just thinking about it…