Wash the potatoes and cook in boiling salted water until tender. Drain, leave to cool slightly, then peel. Clean the chanterelles thoroughly. Peel and dice the onion. Set aside.
For the meatballs, soak the bread roll in lukewarm milk in a bowl. Peel and finely chop the onions. Wash the parsley, shake dry and finely chop the leaves. Melt the butter in a pan and fry the onions until translucent. Remove from the heat and stir in the parsley. Squeeze the bread thoroughly. Knead well with the veal, egg, mustard, salt, pepper, lemon zest and onion-parsley mix in a bowl with your hands.
Using damp hands, shape the mix into meatballs.
Heat the oil in a pan and add the meatballs. Lightly press the meatballs with the spatula and sauté each side for 4-5 minutes.
Fry the chanterelles and diced onion in a large pan in butter until softened.
Deglaze with the white wine, simmer to reduce then pour in the cream.
Season the chanterelle cream with salt and pepper and remove from the heat.
Heat the milk and cream in a saucepan. Press the peeled potatoes through a potato rice into the hot milk mixture.
Stir in the butter and season with salt, pepper and nutmeg. Finally add the croutons. Serve the veal patties with the mashed potatoes and chanterelle cream on plates and sprinkle with chopped chives.