Clean and wash the zucchini and cut them in half lengthwise. Cut sausages and zucchini into slices. Peel, wash and chop the potatoes.
Preheat the oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2). Heat 1 tablespoon of oil in an ovenproof, coated pan with a high rim. Fry the sausage for 3-4 minutes while turning it over. Add potatoes and fry for 6-8 minutes, turning.
In the meantime, whisk the eggs and milk for the egg milk. Season with salt, pepper and a little nutmeg. Wash oregano, shake dry, chop coarsely and stir in.
Add zucchini and penne to the potatoes and fry for 2-3 minutes. Pour egg milk over them. Leave to rise for 5-6 minutes over a low heat, then finish setting in a hot oven for 12-15 minutes.