Take the peppercorns and using a pestle and mortar grind them gently. Don't grind them to flour they need some texture.
Melt the butter at low heat in a saucepan and then fry the shallots for 5 minutes.
Add the rest of the ingredients: Peppercorns, cream, mustard, brandy, crumble in the stock cube, and pour in 125ml of boiling water.
WHen everything is in place stir it all together and leave to simmer for 10-20 minutes. Stir regularly, until you’re happy with the thickness of the sauce.
And then, season generously with salt and serve right away.