Put the beef strips into a shallow bowl. Combine the soy sauce, wine or sherry, ginger and 1 tablespoon of oil together, then pour over the strips, basting to coat them thoroughly. Set aside to marinate for 15 minutes, stirring and basting occasionally. Meanwhile, cut the broccoli into bite-sized pieces.

Heat the remaining oil in a frying-pan. Add the beef mixture and stir-fry for 1 1/2 minutes. Using a slotted spoon, transfer the beef strips to a plate. Add the stock to the pan and bring to the boil. Add the broccoli and cook for 1 minute, stirring constantly. Reduce the heat to low, cover and simmer the mixture for 4 minutes. Using the slotted spoon, transfer the broccoli to a warmed serving dish. Keep hot.

Add the vegetable fat to the pan and melt it. Return the beef strips to the pan and stir-fry for 30 seconds. Add the cornflour (cornstarch) mixture and stir-fry for 1 minute, or until the sauce becomes translucent. Remove from the heat.

Arrange the beef strips over the broccoli, then pour over the sauce. Serve at once.