1. Prepare the Café de Paris butter
Combine the softened butter with the herbs, curry powder, gherkin, capers, garlic, shallot and egg yolk. Season with salt and cayenne pepper, then mix until evenly combined. Shape into a log, chill until firm, then slice into discs.
2. Prepare the onion rings
Cut eight thick rings from the centre of the onion and soak them in milk overnight. Make a batter with the flour, Trisol and sparkling water, then chill for around an hour.
When ready to cook, dust the onion rings in seasoned flour, dip them into the batter and deep-fry at 180°C for 2–3 minutes until crisp and golden.
3. Make the triple-cooked chips
Cut the potatoes into chips and rinse under cold water to remove some of the starch. Steam for 30 minutes, then cool completely.
Deep-fry at 140°C for 10 minutes, remove and cool again. For the final cook, fry at 180°C for around 6–7 minutes until golden and very crispy. Season with salt and finish with chopped parsley.
4. Make the green peppercorn sauce
Sweat the shallots with the peppercorns. Add the brandy and reduce until dry.
Add the chicken stock and reduce by half, then add the cream and reduce by half again. Stir through the Dijon mustard and Cabernet Sauvignon, then add the spinach and blend. Finish with a further 500ml of cream and season with salt to taste.
5. Cook the steaks
Cut the fillet into four steaks and season generously with salt. Heat a large heavy-based frying pan over a medium heat, then add the butter.
Brown the steaks on both sides until deeply coloured, then remove any cling film and colour the edges evenly. Cook medium-rare, or to your preferred doneness, then rest on a warm plate for 10 minutes.
Deglaze the pan with lemon juice and pour the resulting juices over the resting steaks.
6. Serve
Briefly warm the rested steaks under a hot grill if needed. Place a steak in the centre of each plate, top with a disc of Café de Paris butter and a couple of crispy onion rings. Serve with the triple-cooked chips and green peppercorn sauce.
