Melt 30 g butter in a pan
Add ½ brown onion (finely chopped) with 8 g cracked black pepper or ground black pepper , 2 tsp dijon mustard and 1 tbsp red wine vinegar and cook until softened (approx 5 mins)
Dissolve 1 chicken stock cube in 150 ml water, add to sauce and simmer for 5 mins
Then pour in 150 ml double cream and simmer for another 5 minutes or so
Optional: add peppercorn sauce to the pan you cooked the steaks in and 'de-glaze' the pan with the sauce to pick up all of the steak juices and deepen the flavour
