Heat the oil in a large saucepan. Stir in the onion, chestnut mushrooms and shiitake mushrooms and fry for 2 minutes or until beginning to soften. Stir in the red pepper and broccoli florets and continue to fry, stirring, for 3–4 minutes.
Stand back from the pan, pour in the brandy and set light to it.
Pour in the stock and the Worcestershire sauce and bring to the boil. Cover the pan, reduce the heat and simmer for about 5 minutes or until the broccoli is just tender.
Stir in the creamed horseradish, if using, and the soured cream. Season to taste and serve immediately.