Cut the beef fat into small pieces and cover with rapeseed oil. Allow it to gently simmer so the fat renders down. Once the fat is cooked through (shrivelled and brown) drain the oil and set aside.
Wash the potatoes and cut into generous size chips, and blanch in salted water with the rosemary and garlic clove.
When cooked take out and allow to cool. Then heat the beef fat oil to 140.c and allow the chips to colour and allow to cool again.
Season the fillet steaks with a generous helping of black pepper and salt, then place into a hot pan with a little oil for about 5 minutes, so they have a nice colour on all sides.
Take the steaks out the pan and allow to rest then, Once the pan has cooled a little add the butter and allow it to melt.
Next dice the garlic and shallots and allow to sweat in the butter on a medium heat, once soft add the pink peppercorns and brandy then flambe.
Add the red wine and allow to reduce by half, then add the double cream and bring the sauce to a simmer.
Place the fillet steaks back into the pan and allow to cook further, deglazing the steaks as they heat. It is best cooked no further than medium rare for the fillets steaks to remain tender and moist.
Finish with freshly chopped parsley and serve with beef fat chips that have been cooked in the beef fat oil till crispy at 180.C, ready to serve.