Preheat the oven to 375F. Lightly grease the inside of a 9" round baking dish.
Slice the zucchini, tomatoes and eggplant slices in ¼ inch slices. Try to cut them in a way that they resemble in size for even baking.
1½ small Zucchini, 1 piece Eggplant, 4 pieces Roma Tomatoes
Stack the slices, alternating between the three veggies, positioning them vertically in the baking dish.
Whisk together in a bowl; the eggs, milk, garlic, onion, salt, herbs, and Dijon mustard.
5 large Eggs, ¼ cup Red Onion, 2 cloves Garlic, 2 teaspoon Herbe de Provence, 1 teaspoon Salt, 1 tablespoon Grainy Mustard
Pour the egg mixture over the vegetables in the baking dish. Place the dish in the preheated oven for 30-35 minutes or until the eggs are set and golden.