Having cooked your steak take it out of the frying-pan and keep it hot. Throw away the fat, but on no account wash the frying-pan, which will be encrusted with delicious caramelised juices.
Put in the chopped onion and a teaspoon of butter and allow to cook fast for 2 minutes, then pour in the wine and add the garlic and thyme. Boil rapidly until only