01 - Set the oven to 400°F (200°C) to begin roasting the vegetables.
02 - Toss zucchini, bell pepper, onion, and cherry tomatoes with olive oil, salt, and black pepper on a baking sheet. Roast for 20 minutes, stirring halfway through, until tender and caramelized.
03 - Lower the oven setting to 350°F (175°C) in preparation for baking.
04 - In a large bowl, whisk together eggs, milk, feta, Parmesan, oregano, and thyme until evenly blended.
05 - Stir roasted vegetables and fresh spinach leaves into the egg mixture gently.
06 - Pour the combined mixture into a lightly greased 9-inch (23 cm) oven-safe skillet or baking dish.
07 - Bake for 15 to 18 minutes, or until the center is firm and the top is lightly golden.
08 - Allow to cool for 5 minutes, then garnish with chopped fresh basil. Slice and serve warm or at room temperature.