Preheat your oven to 180°C (350°F).

Prepare the vegetables: Peel and dice the potatoes. Boil them in a pot of salted water until tender, about 10-15 minutes. Drain and set aside.

Sauté the aromatics: While the potatoes cook, heat 2 tablespoons of olive oil in a large skillet over medium heat. Finely chop the leek and sauté it for 2-3 minutes, until softened.

Add remaining vegetables: Dice the bell pepper and grate the carrot. Add them to the skillet with the leek and cook for another 5 minutes, stirring occasionally.

Shred the cabbage: Finely shred the cabbage. Add it to the skillet and cook for another 5 minutes, or until it starts to soften. Season with salt and pepper to taste.

Whisk the egg mixture: In a large bowl, whisk together the eggs, milk, flour, and baking powder until smooth.

Combine everything: Combine the cooked and drained potatoes, the sautéed vegetables, and the egg mixture in a large bowl. Stir well to ensure everything is evenly distributed.

Bake: Grease a baking dish with the remaining olive oil. Pour the casserole mixture into the prepared dish and spread it evenly. Sprinkle the grated cheese on top.

Bake for 30-35 minutes, or until the top is golden brown and a toothpick inserted into the center comes out clean.

Cool and serve: Let the casserole cool slightly before serving. Enjoy warm!