Lightly roast the chopped walnuts in the oil, being careful not to get too dark. Add the apple pieces and sauté them while stirring (they shouldn`t get too soft but still have a bit of bite). Deglaze with a dash of balsamic vinegar and simmer gently. Season to taste with sugar, salt and pepper.
Very tasty with lamb`s lettuce, e.g., in combination with fried poultry strips.