Wash the savoy cabbage leaves, blanch in boiling salted water for 3-4 minutes, remove, rinse in cold water and pat dry well.
Cut out the thick leaf ribs and spread out the leaves on a work surface.
For the filling, peel and coarsely grate the potatoes.
Chop the chestnuts coarsely and fry with the potatoes in a pan with 2 tbsp melted butter for 3-4 minutes.
Wash the spring onions and cut into fine rings.
Remove the pan from the heat and stir in the spring onions, parsley, cheese, sour cream and breadcrumbs and season with salt and pepper.
Place some of the mixture in each cabbage leaf.
Roll up each leaf to enclose the filling.
Tie with kitchen string.
In a pan, melt the clarified butter and sauté the cabbage rolls to brown on all sides. Pour in the stock and cook over a medium heat for 40 minutes. Remove the string and serve.