Peel and cook the potatoes and carrots until tender.
Cook the cabbage separately until soft. Drain well.
If using canned peas, drain them thoroughly.
Finely chop all the cooked vegetables and combine them in a large mixing bowl.
Melt 50 g of the butter and stir it into the vegetables.
Separate the eggs.
Mix the egg yolks with the milk and season with salt.
Beat the egg whites until stiff peaks form.
Fold the whipped egg whites gently into the egg yolk mixture.
Carefully combine the egg mixture with the vegetables.
Grease a baking dish with the remaining butter.
Transfer the mixture to the baking dish and sprinkle with fresh breadcrumbs.
Bake at 190°C (375°F) for about 20 minutes, or until lightly golden and puffed.
Brush the top with the remaining melted butter before serving.