- Rinse and finely chop sage. Clean the mushrooms and halve.
- Fry sage and mushrooms with the pickled onions in a few glugs of olive oil in a pan. Stir occasionally until ingredients start to turn brown. Add chestnuts and sauté.
- Add the tomato paste and gravy and gently stir for about 5 minutes while stirring. Deglaze with red wine and water and simmer on low heat for about 20 minutes until the chestnuts are tender. Add the smoked salt and parsley and mix well. Sauté the seitan shortly before serving in the rapeseed oil and pour into the finished sauce.