This sauce can be made with extra mushrooms, and using vegetable stock cube for a veggie version, perhaps a nice sauce for the Spicy Bean & Mozzarella Roasts.
Shallots can replace onions for a sweeter flavour; the ratio is roughly 4 small shallots to 1 small onion.
Turn off the heat (if using a gas hob) when you add the brandy, or it may ignite and catch you unawares........
Steaks can be pan fried or grilled, then sliced into 1-2cm strips and then added to the sauce. Otherwise they can be cut into strips and stir fried quickly.
If the sauce thickens too much, add a little water to let down the sauce, do not add cream.