Preheat the oven to 180°C (350°F).

Bring a pot of water to a boil. Add the cauliflower and broccoli florets and blanch for 3 minutes. Drain and set aside to cool slightly.

In a large mixing bowl, whisk together the eggs, heavy cream, salt, black pepper, and oregano.

Add the blanched cauliflower, broccoli, diced sweet pepper, and halved cherry tomatoes to the egg mixture. Stir well to ensure all the vegetables are evenly coated.

Grease a baking dish and pour the vegetable and egg mixture into it. Spread the mixture evenly.

Sprinkle the grated cheese over the top of the casserole.

Bake in the preheated oven for 25-30 minutes, or until the cheese is golden brown and bubbly, and the vegetables are tender.

Remove from the oven and let cool for a few minutes before serving.