Cut the rolls into slices and drizzle with the wine. Grease a shallow gratin dish with butter (a quarter of the mixture). Melt the remaining butter and sauté the onions in it. Layer the slices of bread and cheese in the form of a roof tile. Mix eggs and whipped cream, season with salt and pepper and pour over the casserole. Spread the steamed onions evenly over the top and bake the whole thing in a heated oven at 200 °C for about 20 to half an hour. Before serving, garnish with finely chopped chive rolls.
This culinary specialty is particularly appreciated on the Rhine and Moselle rivers. Therefore, a dry white wine of the region, e.g. a Riesling, goes well with this dish.
Our tip: Always use fresh chives if possible!