Cook the potatoes in the oil and butter for 10 minutes; add the bread and cook for another 5 minutes.
Separate the eggs, beat the yolks together with the wine. Whisk the egg whites until they form soft peaks and fold into the yolks.
Heat the butter in a clean pan, add the eggs and cook for a few minutes, then spread over the potato and bread cubes, the sausage and the tomato. Cook for a few minutes.
Sprinkle with cheese and brown under the grill until the cheese melts. Eat immediately.