Wash the zucchini, cut into long, about 1 cm thick slices, salt them well, and let stand for 15 minutes to release excess water.
Boil salted water in a pot, add the zucchini slices, and cook for 3-4 minutes, until lightly tender but still with some bite - be careful not to overcook.
Remove with a slotted spoon, let cool and drain.
Layer the slices in an oven-safe dish, drizzling a spoonful of sour cream over each layer.
Sprinkle the top with breadcrumbs, then drizzle with the melted butter.
Bake in a preheated oven at 190°C for 25-30 minutes, until the top is golden and crisp.
Serve warm.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.