Preheat oven to 190°C and brush a pie dish with oil.
Heat a frypan over medium heat with oil and cook onion for a few minutes until onion begins to soften.
Add garlic, zucchini, carrot and silverbeet and sauté for a few more minutes until cooked. Set aside to cool.
Combine eggs, mustard and 3/4 of the parmesan, season with salt and pepper and stir through vegetable mix.
Pour mixture into prepared pie dish, top with remaining cheese and bake for 25 minutes or until set.
Toss cucumber, tomato, red onion, avocado, parsley and vinegar, season with salt and pepper and serve with pie.