Start by steaming fresh broccoli and cauliflower in a pot with a steamer basket over boiling water for 15-18 minutes until they are tender but vibrant. Once cooked, drain the veggies well and set them aside to allow excess moisture to escape.

In the same pot, add a splash of olive oil and sauté the diced onion over medium heat for about 2 minutes until it becomes translucent. Then, mix in the spinach and minced garlic, cooking until the spinach is wilted and fragrant.

In a large mixing bowl, whisk together the eggs, Greek yogurt, and milk until smooth. Then, incorporate the shredded rotisserie chicken, half of the cheese, the steamed vegetables, and the cooled onion-spinach mixture. Season with herbs and spices, mixing thoroughly.

Preheat your oven to 375°F (190°C). Lightly grease a 9x13 baking dish and pour in the mixed contents from the bowl. Top with the remaining cheese and crushed parmesan crisps. Bake for about 35 minutes, or until the top is golden brown and bubbly.

Once baked, let the casserole rest for about 10 minutes. Optionally, garnish with fresh parsley before serving.