150mlbeef stock(or chicken if you don't have beef)
2 tsp green peppercorns or a mix of various peppercorns
Using the same pan your steak was cooked in, add the chopped shallots and cook until softenAdd in the cognac, brandy (or red wine vinegar) to deglaze the pan i.e. take off the nice bits of brown from cooking the steak) and bring to a quick simmer.
Add the stock and reduce by half over a high heatAdd the peppercorns and using a spoon or a pestle, gently crush a few peppercornsSeason if necessary and stir in 4 tbsp double cream
Simmer (don’t boil) for 1 or 2 mins until the sauce is slightly thickened and the peppercorns have softened and mellowed in flavour
TIP: using the back of a spoon cover it with sauce. If the sauce stays on it, then it’s done.