Steps
1. Preheat the oven to 375°F (190°C).
2. In a skillet, heat olive oil over medium heat. Add diced potato and sauté for 5 minutes until slightly tender.
3. Add grated carrot and chopped cabbage to the skillet, cooking for another 3-4 minutes until softened. Season with salt and pepper.
4. In a bowl, whisk the egg whites until frothy. Fold in the sautéed vegetables.
5. Place the slice of bread in a small, greased baking dish, pressing it down to form a base.
6. Pour the vegetable and egg white mixture over the bread, spreading it evenly.
7. Bake in the preheated oven for 15-20 minutes or until the egg is set and golden on top.
8. Remove from oven, let cool slightly, then slice and serve garnished with fresh herbs if desired.